Water column process rate measurements from water collected aboard the R/V Endeavor cruise EN559 in the northern Gulf of Mexico from 2015-05-31 to 2015-06-02

This dataset contains water column process rate measurements from water collected aboard the R/V Endeavor cruise EN559 in the northern Gulf of Mexico from 2015-05-31 to 2015-06-02. Samples were collected during cruise EN559 using a CTD-rosette. The objective was to determine water column process rates at ECOGIG seep and other study sites. The ship departed Gulfport, Mississippi on 2015-05-29 and collected samples at ECOGIG sites before returning to Gulfport on 2015-06-21. Water samples collected with the CTD-rosette were incubated under simulated in-situ conditions after addition of 15N2 and either 13C-bicarbonate or 13C -methane tracers for 24 (DIC label) or 48h (CH4 label). Experiments were terminated by gentle pressure filtration onto a 10 µm sieve and pre-combusted GF/F filters to collect the small and large size fractions of particles. Filters were dried, then pelletized in Sn (tin) capsules for isotopic analysis. N and C isotopic abundances were measured by continuous-flow isotope ratio mass spectrometry using a Micromass Optima IRMS interfaced to a CE NA2500 elemental analyzer. Rates were calculated using a mass balance approach (Montoya et al. 1996). The dataset also includes the date, depth, and locations (latitudes and longitudes) of the sample collection.