Nitrogen fixation from vertical profiles from CTD rosette samples by stable-isotope mass spectrometry on UKSOLAS cruise D325.

Profiles of Nitrogen fixation using ¹⁵N methodology were determined from 6 different oceanographic stations in the vicinity of the Cape Verde Islands (north-east Atlantic) between 13 November and 18 December 2007 onboard RRS Discovery. Stations were selected from remotely sensed information on surface chlorophyll concentrations to give a gradient of conditions between 0.06 and 0.38 µg L^{. Very high rates were determined at Station B (>24 nmol L^-1h^-1 though at all other stations rates were between 0.01 and 0.26 nmol L^-1h^-1.}