Abstract:

This dataset contains values for potential rates of nitrification and denitrification (denitrification enzyme assays) and rates of greenhouse gas (CO2, CH4, and N2O) production, abundances of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), denitrifying bacteria (nirS), and methane-oxidizing bacteria (MOB) and soil properties collected from 12 marshes in Terrebonne Bay (TB), western Barataria Bay (WB), and eastern Barataria Bay (EB), Louisiana during July 2015. In each region, two pairs of oiled and unoiled marshes were sampled. At each site, 5-cm deep soil cores were collected at 2 replicate plots at each of 2 distances from the marsh edge (1 and 10m). Each sample was analyzed for potential nitrification rates, potential denitrification rates, and greenhouse gas (CO2, CH4, and N2O) production rates in soil slurries with AOA, AOB, nirS, with MOB abundances also being quantified. Additionally, a series of basic site characterizations were measured: soil properties, soil extractable nutrients, porewater, overlying water and adjacent bay water depth, temperature, salinity, specific conductance and nutrients, when available.

Suggested Citation:

Roberts, B.J., Chelsky, A.. 2019. Marsh soil nitrification, denitrification and greenhouse gas production rates, microbial communities, and explanatory variables collected from marshes in Terrebonne Bay, western Barataria Bay, and eastern Barataria Bay, Louisiana in July 2015. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/JWD68GNA

Purpose:

This dataset was developed as part of a research project investigating the effects of the Deepwater Horizon oil spill on salt marsh biogeochemistry. This component of the Coastal Waters Consortium research effort addressed the following questions: 1) Do marsh soil biogeochemistry rates vary spatially across the Louisiana coast and/or with marsh position?, 2) What are the primary drivers of these biogeochemical rates?, 3) Do these drivers differ by biogeochemical process and or by region?, and 4) Are these results different between oiled and unoiled marshes.

Data Parameters and Units:

Region-site ID: User-defined identifier assigned to each sampling site. Identifier contains a region code (TB=Terrebonne Bay, WB= western Barataria Bay, EB=eastern Barataria Bay) and a site number designation, Region: Region of sample collection (TB=Terrebonne Bay, WB= western Barataria Bay, EB=eastern Barataria Bay), Site: Site number designation, Latitude (decimal degrees), Longitude (decimal degrees), Oil status: Indicates whether the marsh received Macondo Oil (Oiled) or not (Unoiled), Plot: Plot identifier along the sampling transect referencing long term distances (0 = 1m and 2=10m) with replicate plot indicated (A or B), Distance (m): Distance from the marsh edge of the sampling plot (meters), Month-Year: Indicates the month and year that samples were collected or measurements made (MMM-YY), Nitrification potential (nmol NO3-N gdw-1 d-1): rate of nitrification potential in the top 5 cm of soil at the plot, Denitrification potential (nmol N2O gdw-1 d-1): rate of denitrification potential determined using the denitrification enzyme assay (DEA; acetylene-block technique) in the top 5 cm of soil at the plot, CO2 production (nmol gdw-1 d-1): carbon dioxide production rate (soil slurry measurement) in the top 5 cm of soil at the plot, CH4 production (nmol gdw-1 d-1): methane production rate (soil slurry measurement) in the top 5 cm of soil at the plot, N2O production (nmol gdw-1 d-1): N2O production rate (soil slurry measurement) in the top 5 cm of soil at the plot, AOA abundance (amoA gene copies gdw-1): abundance of ammonia-oxidizing archaea in top 5 cm of soil at the plot (expressed in amoA gene copies per gram dry weight), AOB abundance (amoA gene copies gdw-1): abundance of ammonia-oxidizing bacteria in top 5 cm of soil at the plot (expressed in amoA gene copies per gram dry weight), Denitrifier abundance (nirS gene copies gdw-1): abundance of denitrifying bacteria in top 5 cm of soil at the plot (expressed in nirS gene copies per gram dry weight), MOB abundance (pmoA gene copies gdw-1): abundance of methane-oxidizing bacteria in top 5 cm of soil at the plot (expressed in pmoA gene copies per gram dry weight), soil T (°C): soil temperature at the plot in degrees C, soil pH: pH of the top 5 cm of soil at the plot, soil Eh: soil redox potential (Eh) in the surface soil of the plot (units = mV), soil bulk density (g/cm3): bulk density of the top 5 cm of soil at the plot, soil water content (%): gravimetric water content of the top 5 cm of soil at the plot, soil organic matter (%): organic matter content determined via loss on ignition (LOI) of the top 5 cm of soil at the plot, soil organic C (%): organic carbon content of the top 5 cm of soil at the plot, soil total N (%): total nitrogen content of the top 5 cm of soil at the plot, soil total P (µg/g): total phosphorus content of the top 5 cm of soil at the plot, soil CN (mol:mol): organic carbon to total nitrogen ratio of the top 5 cm of soil at the plot, soil NP (mol:mol): total nitrogen to total phoshorus ratio of the top 5 cm of soil at the plot, soil CP (mol:mol): organic carbon to total phosphorus ratio of the top 5 cm of soil at the plot, Benthic chlorophyll (mg/cm2): benthic chlorophyll of the top 5 cm of soil at the plot, Benthic phaeopigments (mg/cm2): benthic phaeopigments of the top 5 cm of soil at the plot, soil extractable NO3+NO2 (micromols per grams dry weight of soil): extractable nitrate + nitrite concentration of the top 5 cm of soil at the plot, soil extractable NH4 (micromols per grams dry weight of soil): extractable ammonium concentration of the top 5 cm of soil at the plot, soil extractable PO4 (micromols per grams dry weight of soil): extractable orthophosphate concentration of the top 5 cm of soil at the plot, Porewater salinity (psu): salinity of porewater from the plot, Overlying water depth (cm): depth of overlying water at plot, Overlying water temp (°C): temperature of overlying water at plot, Overlying water salinity (psu): salinity of overlying water at plot, Overlying water specific conductance (mS): specific conductance of overlying water at plot, Overlying water NO3-N + NO2-N (micromols per liter): dissolved nitrate + nitrite concentration of overlying water at the plot, Overlying water NH4-N (micromols per liter): dissolved ammonium concentration of overlying water at the plot, Overlying water PO4-P (micromols per liter): dissolved orthophosphate concentration of overlying water at the plot, Overlying water SiO2 (micromols per liter): dissolved silicate concentration of overlying water at the plot, Baywater temp (°C): temperature of baywater adjacent to site (in degrees C), Baywater salinity (psu): salinity of baywater adjacent to site, Baywater specific conductance (mS): specific conductance of baywater adjacent to site, Baywater NO3-N + NO2-N (micromols per liter): dissolved nitrate + nitrite concentration of baywater adjacent to site, Baywater NH4-N (micromols per liter): dissolved ammonium concentration of baywater adjacent to site, Baywater PO4-P (micromols per liter): dissolved orthophosphate concentration of baywater adjacent to site, Baywater SiO2 (micromols per liter): dissolved silicate concentration of baywater adjacent to site.

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