Soil nitrification potential rates in marsh mesoscosms prior to oiling: July 2018-June 2019

Marsh soil nitrification rates were determined approximately bi-monthly at the Louisiana Universities Marine Consortium (LUMCON) saltmarsh mesocosm facility in Cocodrie, Louisiana. These twelve hydrologically-isolated, large (~3m diameter) mesocosms were planted with intact Spartina alterniflora and soil sections in January 2018. In July, September, and November 2018 and January, March, May, and June 2019, 5 out of 25 possible central grids were randomly selected to be sampled within each marsh mesocosm. A 0.25m x 0.25 m quadrat was randomly placed within each grid and a 2.6cm diameter core was taken from each plot and all 5 cores were pooled into a single whirlpak bag to generate a homogenized sample capturing the spatial heterogeneity across each mesocosm. The soils were then incubated to determine nitrification potential rates following the methods described in Marton et al. (2015) and Schutte et al. (2020). This dataset represents results prior to the addition of oil to some of the mesocosms as part of large-scale oiling experiment initiated on 2019-07-08.