Rotifers colonising sediments with shallow gas hydrates.

Rotifers, one of the smallest metazoans, are only seldom found in marine environments. Surprisingly, we discovered high abundances of at least two new species of rotifers settling in anoxic and highly sulphidic sediments associated with shallow gas hydrates (GH) at the southern crest of Hydrate Ridge off Oregon, NE Pacific, in a water depth of about 780 m. At basins adjacent to Hydrate Ridge, 1,285-2,304 m deep, we found rotifers co-occurring with the sulphide-oxidising bacteria Thioploca sp.