Abstract
The benthic ecology of the Beatrice Oilfield area is described from preproduction surveys carried out in 1977, 1980 and 1981. and from earlier published information. Variations in the water depth (from 33m to > 60 m) over the area were mirrored by sedimentary and faunal gradients. The sediments ranged from very fine, through fine to medium sands and were inhabited by faunal communities characterised by Thyasira flexuosa, Tellina fabula and Tellina pygmaea, respectively. Two fades of the fine sand community were noted, typified by the abundance of Thyasira flexuosa in muddier sediments and Crenella decussala in coarser deposits. Localised patches of shell gravel in which the fauna was characterised by reduced densities of Tellina fabula with elevated numbers of Scoloplos armiger and Lumbrineris gracilis occurred in medium depths. Examination of the faunal composition indicates that the Beatrice Oilfield lies at the interface between Glemarec's infralittoral and coastal étages.
Comparison with earlier reports of the benthic communities of the area suggests a degree of long term persistence of the fauna in qualitative and quantitative terms. A list of all taxa found during the recent surveys is given; this includes a number of new records from the North Sea.