Benthic macrofauna abundance from megacore samples in Whittard Canyon during cruise JC036 during summer 2009.

Macrofauna and polychaete species abundance data were obtained from replicate megacore samples, collected from three branches inside the Whittard Canyon (N.E. Atlantic) and one site on the adjacent slope to the west of the canyon during cruise JC036 in June and July 2009. Samples were collected using a Megacorer. Four sites were sampled, three in the Whittard Canyon branches (Western, Central and Eastern) and one site on the slope to the west of the canyon. All sites were located at 3500 m depth. The Megacorer was fitted with eight large (100 mm internal diameter) core tubes. Five deployments were conducted in the Western branch, six in the Central and Eastern branches and five at the slope site. One extra deployment was made in the Central and Eastern branches to compensate for the failure to recover sufficient cores. Core slices from the same sediment layer from one deployment were pooled to make one replicate sample. The number of cores pooled per deployment ranged from 3 to 7 and the area of seabed sampled varied accordingly. Samples were fixed with 10 % borax-buffered formalin. In the present study, the top three sediment horizons (i.e. 0-1, 1-3 and 3-5 cm) were analysed in toto. Please see Gunton et al. (2015) for further details. Macrofaunal organisms were extracted from the samples. In the laboratory, macrofauna were transferred from the formalin onto a 300 micro-meter mesh sieve, rinsed with fresh water and sorted in 70 % ethanol. They were identified to higher taxa levels, and polychaetes to species level and counts of species/taxa recorded for each site. AphiaIDs have been assigned to the samples - where identification was only possible to genus or family level, the aphiaIDs for genus and family have been supplied. The supplied aphaIDs are those that were acceptable at the time of the analysis and not their more recent superseding terms. This cruise was part of the HERMIONE project and formed the basis of L. Guntons PhD thesis 'Deep-Sea Macrofaunal Biodiversity of the Whittard Canyon (NE Atlantic)'.