Dando, P. R.; Austen, M. C.; Burke, Jr. R. A.; Kendall, M. A.; Kennicutt, II M. C.; Judd, A. G.; Moore, D. C.; O'Hara, S. C. M.; Schmaljohann, R.; Southward, A. J. (1991). Ecology of a North Sea pockmark with an active methane seep. Marine Ecology Progress Series. 70: 49-63.
Dando, P. R.; Austen, M. C.; Burke, Jr. R. A.; Kendall, M. A.; Kennicutt, II M. C.; Judd, A. G.; Moore, D. C.; O'Hara, S. C. M.; Schmaljohann, R.; Southward, A. J.
Ecology of a North Sea pockmark with an active methane seep
??At a large North Sea pockmark, with active methane seeps, surface sediments were found
to have higher insoluble sulphide concentrations than sedlments from the surrounding area. The fauna
of the pockmark was characterized by 2 species which have not pi-evlously been reported from the
Fladen Ground in the northern North Sea. These species were a b~valveT, hyasira sarsi (which is known
to contain endosymbiotic sulphur-oxidising bacteria) and a mouthless and gutless nematode,
Astomonerna sp., which also contains endosymbiotic bacteria The nematode was the dominant
meiofauna species in the pockmark sediments. Both macro-lnfauna and total nematodes were in low
abundance in samples taken from the base of the pockmark. Sediment samples from the pockmark
contained numerous otoliths, implying that substantial winnowing of the sediment had taken place.
This was supported by studies on the sulphide concentrations in the sediment which showed multiple
layering of the sediments on the sides of the pockmark, suggesting displacement. The carbon isotope
compositions (6I3c) of the tissues of benthic animals from in and around the pockmark were generally in
the range -16 to -2O%, indicating that little methane-derived carbon was contributing to their
nutrition. T sarsi had the most 13c-depleted tissues, -31.4 to -35.1 L, confirming the nutritional
dependence of this species on chemoautotrophic bacteria that utilize reduced sulphur