Abstract:

Radiotracer approach with the addition of 14C-labelled acetate to the seawater was used to determine the microbial assimilation of acetate into particulate cell biomass (as a carbon source), and the oxidation of acetate to carbon dioxide (as an energy source) in the northern Gulf of Mexico as well as through the chemocline of the Orca Basin brine basin. The dataset reports geochemistry of the study sites, oxidation and assimilation rates of acetate, and bacterial production rates. All rate measurements were performed using radiotracer techniques. The effect of various nutrient additions on acetate oxidation and assimilation was also tested from select sites. Data were collected during Cruises EN559 (May 31st to June 20th, 2015) and EN586 (August 8th to 10th, 2016).

Suggested Citation:

Samantha Joye. 2018. Acetate oxidation and assimilation rates measured by radiotracer assays in oil the northern Gulf of Mexico water column. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7Z60MK7

Publications:

Zhuang, G.-C., Peña-Montenegro, T. D., Montgomery, A., Montoya, J. P., & Joye, S. B. (2019). Significance of acetate as a microbial carbon and energy source in the water column of Gulf of Mexico: implications for marine carbon cycling. Global Biogeochemical Cycles. doi:10.1029/2018gb006129

Purpose:

The purpose of these data is to quantify the rate of acetate oxidation and assimilation in seawater.

Data Parameters and Units:

Latitude (decimal degrees N); Longitude (decimal degrees W); Water depth (m); Depth(m); Sampling date (DD/MM/YYYY); Salinity (‰); Na+ (mM); Cl- (mM); Chlorophyll (μg/L); Nitrate (μmol/L); Ammonium (μmol/L); Phosphate (μmol/L); Dissolved organic carbon (DOC, μmol/L); Acetate (μmol/L); Bacterial production (ng C L-1 d-1); Acetate assimilation rate constant (k) (d-1); Acetate oxidation rate constant (k) (d-1); Acetate uptake rate (k) (d-1); N.D.=not determined; B.D.=below detection limit

Methods:

Radiotracer approach with the addition of 14C-labelled acetate to the seawater was used to determine the microbial assimilation of acetate into particulate cell biomass (as a carbon source), and the oxidation of acetate to carbon dioxide (as an energy source). Assuming first-order kinetics, the assimilation or oxidation rate constant of acetate (k, d−1), could be estimated by plotting the fraction of 14C-acetate taken up versus incubation time. k = −ln(1−f)/t where f is the ratio of the recovered 14C counts (assimilation: the particles on the filter; oxidation: 14CO2 production) divided by total 14C-acetate added to the sample, t is the incubation time. The assimilation or oxidation rates were estimated through multiplying rate constant k by acetate concentrations. All rates were corrected by subtracting killed sample counts, which were typically close to the instrument blanks. The total biological uptake rate was calculated from the sum of the assimilation rate and the oxidation rate.

Provenance and Historical References:

Site geochemical data used to calculate rate measurements in this dataset are associated with GRIIDC datasets: R4.x268.183:0007 (EN559) and R4.x268.000:0007 (EN586)

Individual Files: