Ecology of a North Sea pockmark with an active methane seep

Abstract

Surface sediments had higher insoluble sulphide concentrations than sediments from the surrounding area. The fauna of the pockmark was characterized by two species not previously reported from the Fladen Ground: a bivalve Thyasira sarsi (which contains endosymbiotic sulphur-oxidising bacteria) and a mouthless and gutless nematode, Astomonema sp., which also contains endosymbiotic bacteria. The nematode was the dominant meiofauna species in pockmark sediments. T. sarsi had the most 13C-depleted tissues, -31.4 to -35.1‰ confirming the nutritional dependence of this species on chemoautotrophic bacteria that utilize reduced sulphur. -from Authors