AMT17 DOC measurements

AMT17 Dissolved Organic Carbon (DOC) measurements with temperature, salinity and dissolved oxygen ancillary measurements.

(1) National Oceanography Centre, Southampton

This dataset consists of 375 measurements of dissolved organic carbon (DOC) concentration made on samples collected during the Atlantic Meridional Transect programme cruise 17 (AMT17) between 15 October and 28 November 2005. Also included are the associated depth, position, temperature, salinity and oxygen data. The cruise track passed through both northern and southern Atlantic gyres between the UK and South Africa. Samples were collected on a daily basis at 10 to 12 depths in the upper 300m using a CTD rosette with 24 x 20l OTE (Ocean Test Equipment) bottles and a Sea-Bird 911 CTD equipped with a Seabird oxygen sensor. 250ml samples were filtered using an acid washed all glass filtration apparatus through GF/F filters which had been ashed at 450°C for 16hrs. A subsample was then sealed in an ashed ampoule after acidification to pH<2 using Aristar Hydrochloric acid. They were then stored in a fridge until analysis in the National Oceanography Centre, Southampton. This was performed using high temperature catalytic oxidation (HTCO) techniques using a Shimadzu TOC-5000A. Deep Sargasso sea water provided by D Hansell (Miami) was used as a reference material: daily analyses of this water gave concentrations of 45.2 +/- 1.2 micromolar compared to a nominal value of 44–46 micromolar. The analytical precision, calculated using the coefficient of variation of consecutive injections, was 0.1%.