Dataset: Bulk sediment isotope data
Deployment: Spivak_2012

Methodology from Spivak, AC and J Ossolinski. 2016. Limited effects of nutrient enrichment on bacterial carbon sources in salt marsh tidal creek sediments. Marine Ecology Progress Series. 544:107-130. 10.3354/meps11587

Sediment samples for organic matter composition were collected by placing a hard plastic sleeve around a polyvinyl chloride (PVC) corer (5 cm diameter x 15 cm deep) and then removing the corer. The plastic sleeve remained in place to maintain the integrity of the sediment column and mark the core location. The top 0.5 cm of each core was collected into pre-combusted vials and frozen (-80 deg C) until analysis for total organic carbon content and stable isotopes (d13C). Samples were dried to constant mass (60 deg C), homogenized with a Retsch Mixer Mill 200, and acidified to remove carbonates prior to analysis by the WHOI Organic Mass Spectrometry Facility with a Carlo Erba 1108 elemental analyzer interfaced to Finnigan-MAT DeltaPlus isotope ratio mass spectrometer (IRMS). Isotopic data are reported as d-values in units of per mil (0/00). For sediments from the isotope labeling experiments, resulting d-values were converted to atom % to calculate excess 13C (absolute amount 13C incorporated), using the equations:

where VPDB is the Vienna Pee Dee Belemnite standard (0.011237) and concentrations are expressed in moles carbon per m2, by accounting for sediment bulk density (0.52 g cm-3) and core depth (0.5 cm). Sediment samples collected just prior to application of 13C-labeled NaHCO3 or S. alterniflora detritus served as controls.