Shelf Sea Biogeochemistry (SSB) benthic epifaunal abundance and individual megafaunal measurements during RRS Discovery cruises DY021, DY030 and DY034.

This data set contains epifaunal and megafaunal data collected from Jennings beam trawls conducted in the Celtic Sea. The samples were collected during RRS Discovery cruises DY021, DY030 and DY034 between March-August 2015, as part of the UK Shelf Sea Biogeochemistry research programme (UK-SSB). Three x 2m Jennings beam trawls at 3 each of the 4 main benthic (A,G,H,I) sites were deployed to quantify the community structure and biomass of large epifaunal organisms. Epifaunal measurements are associated to individual trawl events. Individual large taxa measurements were also taken from random samples from the main sites in order to validate and quantify large taxa found using the autosub images and are not associated to individual trawl events. On recovery the fauna were preserved with 10% buffered formaldehyde solution. This residue was returned to the Plymouth Marine Laboratory (PML), UK, where the fauna were extracted, identified to species level where possible, and biomassed (blotted wet weight) to species level. Molluscs and crustaceans were subsequently decalcified by soaking in 10% formic acid solution. Animals were then rinsed in water, blotted and re-weighed. The author does not have any concerns over the quality of the data set and values are consistent with similar data reported in the wider literature. The data were collected as part of the Shelf Sea Biogeochemistry (SSB) research programme as part of the Biogeochemistry, Macronutrient and Carbon Cycling in the benthic layer (BMCC) research programme. SSB was co-funded by the Natural Environment Research Council (NERC) and the Department for Environment, Food and Rural Affairs (Defra). The programme took a holistic approach to the cycling of nutrients and carbon and the controls on primary and secondary production in UK and European shelf seas, to increase understanding of these processes and their role in wider biogeochemical cycles. The British Oceanographic Data Centre (BODC) created the metadata entry and is responsible for holding master copies of the data.