L'Atalante basin
The dark grey anoxic sediments at the bottom of L'Atalante lake are covered with a  loose black layer. Microbes found in the sediments are almost all (90%) various species of Bacillus. In 2010, three metazoan species, all in the Loricifera phylum, were discovered living in the sediment, the first multicellular lifeforms known to live entirely without oxygen.