Shelf Sea Biogeochemistry sediment characterisation.

This data set contains sediment characterisation data collected from NIOZ cores in the Celtic Sea across four surveys (DY008, DY021, DY030, DY034) on-board the RRS Discovery (2014-2015). The data were collected at four sampling sites (A, G, H, I) and over a spatial survey carried out on DY021. 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. Samples for sediment characterisation were collected using the NIOZ box corer with 300mm diameter cylindrical barrel. Clear plastic tubes were then inserted into the sediment to collect undisturbed sediment cores for Particle size analysis (PSA)/Organic carbon and Nitrogen (OCN) and syringes with the barrel end cut off were used to collect cores for Rapid fines assessment (RFA) and Porosity/Chlorophyll. All samples were then sliced to known depths. PSA was carried out following the NMBAQC method using a combination of sieve and laser diffraction (Mason 2011). OCN was determined from freeze dried sediment, which was ground and analysed using the Carlo Erba EA1108 Elemental analyser (Kirsten, 1979). RFA was completed through image analysis in Adobe Photoshop CS5 using a novel method (Silburn et. al In Prep). Sediment Chlorophyll samples were freeze dried and a known weight (~0.5g) of dried sediment was extracted in 90% acetone using a modified method of that described by Tett et al (1987). The extracted pigment was then measured using either spectrophotometry (DY008) (HMSO 1980) or fluorescence (DY021, DY030, and DY034) (Tett et al 1987). Porosity samples were weighed, freeze dried and weighed again to get the dry:wet sediment weight ratio (Danielson and Sutherland 1986). Permeability was then calculated from porosity (Engelund 1953). 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. Sample collection in the field carried out by Briony Silburn, Dave Sivyer, Claire Mason, Paul Nelson, Stefan Bolan (Centre for Environment Fisheries and Aquaculture Science) and Charlie Thompson (Ocean and Earth Science, University of Southampton). The British Oceanographic Data Centre (BODC) created the metadata entry and is responsible for holding master copies of the data.