Abstract:

Dataset contains information on vegetation and oiling metrics for plots representing different operational and experimental cleanup and restoration treatments for Deepwater Horizon oiled salt marshes in Barataria Bay, Louisiana. Each treatment consists of 5 sites measured once a year from 2013-2015. Treatments include reference sites, oiled control (not treated or planted) sites, mechanical treatment sites (not planted), and mechanical treatment and planted sites.

Suggested Citation:

Zengel, Scott, Nicolle Rutherford, Brittany M. Bernik, Jennifer Weaver, Mengni Zhang, Zachary Nixon, and Jacqueline Michel. 2020. Planting after Shoreline Cleanup Treatment Improves Salt Marsh Vegetation Recovery Following the Deepwater Horizon Oil Spill. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/R47H21AC

Publications:

Zengel, S., Rutherford, N., Bernik, B. M., Weaver, J., Zhang, M., Nixon, Z., & Michel, J. (2021). Planting after shoreline cleanup treatment improves salt marsh vegetation recovery following the Deepwater Horizon oil spill. Ecological Engineering, 169, 106288. doi:10.1016/j.ecoleng.2021.106288

Purpose:

Data was collected to evaluate the efficacy of cleanup methods and vegetation planting on recovery of salt marshes impacted by the Deepwater Horizon Oil Spill.

Data Parameters and Units:

Site ID, year (year of sampling; all sampling conducted in September and early October; 2013, 2014, 2015), treatment (oiled control; reference; mechanical treatment, planted; mechanical treatment), surface oil cover (%), soil tPAH (mg/kg), Spartina alterniflora cover (%), Juncus roemerianus cover (%), Paspalum vaginatum cover (%), total vegetative cover (%), and vegetation height (cm), Lon_DD (Longitude of plot centroid, in decimal degrees (WGS84)); Lat_DD (Latitude of plot centroid in decimal degrees (WGS84))

Methods:

This study was conducted in the northern Barataria Bay “marsh treatment test area” established under the Deepwater Horizon emergency response, located near Bay Jimmy, Louisiana. The oiled control plots, mechanical treatment plots, and mechanical treatment plots with planting used in this study were all located within the same continuous and consistent band of heavy oiling. Reference plots were selected randomly within the nearest contiguous and comparable shoreline area that did not have heavy persistent oiling at the onset of the marsh treatment tests and marsh vegetation structure remained intact during and after the spill. Sampling plots were positioned on the seaward marsh edge, each spanning 5 meters (m) along shore and extending 3 m into the marsh interior. Reference plots were selected randomly within the nearest contiguous and comparable shoreline area that did not have heavy persistent oiling at the onset of the marsh treatment tests and marsh vegetation structure remained intact during and after the spill. Five replicate plots were sampled for each oiling/treatment class, including reference. Sampling for this study was conducted in September/early October over three years, from 2013-2015, at three to five years following initial oiling and two to four years following mechanical treatments and planting. Surface and subsurface oiling descriptions, including oil cover, thickness, and character were based on standardized shoreline assessment methods and terminology applied within each plot (NOAA, 2013; Zengel et al., 2015). Subsurface oiling was visually examined by digging at least two to three shovel test pits per plot to ~20 cm depth and describing oiling distribution, thickness, and character. Shovel test pit locations included at least two haphazardly selected locations within each plot and, where applicable, one or more targeted locations based on geomorphic, surface oiling, and vegetative cues. Surface oiling cover and vegetation cover by species and in total were estimated across each plot, using both visual cover estimation charts and repeated quartering of the plots as needed. Cover estimates were initially made by two independent observers who then compared estimates and arrived at a mutually agreed-upon value. Spartina alterniflora vegetation height was estimated using a vertical profile rod marked in cm increments. Subsurface soil samples were collected for chemical analysis using 15 cm diameter cores taken to 10 cm depth, specifically excluding oil and oiled vegetation debris on the marsh surface. Therefore, oil chemistry results represent oil concentrations in the subsurface soils (not oil on the marsh surface). One soil core was collected from each plot per sampling event. TPAH in marsh soils were determined using GC-MS-SIM (gas chromatography-mass spectrometry in selective ion monitoring mode). TPAH included the sum of 45 PAHs, including alkylated homologues, presented as mg/kg.

Instruments:

gas chromatography-mass spectrometry (GS-MS)

Provenance and Historical References:

National Oceanic and Atmospheric Administration (NOAA). 2013. Shoreline Assessment Manual. 4th Edition. NOAA Emergency Response Division, Seattle, Washington. 65 pp. Available at: http://response.restoration.noaa.gov/sites/default/files/manual_shore_assess_aug2013.pdf Zengel, Scott, Brittany M. Bernik, Nicolle Rutherford, Zachary Nixon and Jacqueline Michel. 2015. Heavily oiled salt marsh following the Deepwater Horizon oil spill, ecological comparisons of shoreline cleanup treatments and recovery. PLOS One 10(7): e0132324. https://doi.org/10.1371/journal.pone.0132324

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