Abstract:
Snails, oysters, and mussels were collected and enumerated in three south Louisiana saltmarshes (Terrebonne Bay, Grand Isle, Port Sulphur) in the Spring and Fall of 2013 in oiled-unoiled pairs per region. The original dataset contained in this submission (R1.x139.144-0021_RabalaisInvertebrateData_v1.xlsx) reported invertebrate data in only two broad categories (Mussels and Snails). These samples were later enumerated further into genus and species and that data is contained in the revised file R1.x139.144-0021_InvertebrateData_2013_v2.xlsx. Additionally, invertebrate measurements not originally conducted on these 2013 samples were done later and can be found in GRIIDC Dataset R4.x264.000:0090. Sediment samples were collected in the field at the same time for hydrocarbon analysis and these data were originally reported in R1.x139.144-0021_RabalaisInvertebrateData_v1.xlsx. As noted in the metadata for that dataset, a correction factor had been applied to the total aromatic and total alkane data due to a contaminant having been inadvertently introduced in the oil analytical lab that included this batch of hydrocarbon samples. At the time the version 1 dataset was published, documentation detailing the nature of the contamination and how the correction factors were determined was not yet available. Because that documentation has since been completed, the hydrocarbon data has been removed from the version 2 dataset and replaced with the sample identifiers necessary to find this data in the GRIIDC Dataset R4.x264.000:0056 (LSU/RCAT ID#’s 2013234-01 to 2013234-26 and 2014058-01 to 2014058-26) which contains not only the correction factor documentation but also individual analyte data for these samples.
Suggested Citation:
Rabalais, Nancy. 2019. Intertidal marsh invertebrates in paired oiled/unoiled sites in coastal Louisiana, 2013-04-04 to 2013-12-09. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7SB43PQ
Data Parameters and Units:
File: R1.x139.144-0021_InvertebrateData_2013_v2.xlsx Worksheet: Site Information Site: User-defined identifier assigned to field sites (GI*= W Barataria Bay, N of Grand Isle; PS*= E Barataria, Bay Jimmy, Port Sulphur area; TB*= Terrebonne Bay) Hypothesized Site Exposure Type: User-defined classification of the site at the beginning of the project, in regards to possible Macondo oil exposure (unoiled or oiled). Transect #: Identifier for three individual transects established within each study site Plot #: Plot number assigned based on two sampling distances from the marsh edge (1 m or 10 m from the marsh edge) LAT (decimal degrees): Latitude of the field site LONG (decimal degrees): Longitude of the field site Worksheet: Invertebrate data Site: User-defined identifier assigned to field sites (GI*= W Barataria Bay, N of Grand isle; PS*= E Barataria, Bay Jimmy, Port Sulphur area; TB*= Terrebonne Bay) Date Collected: Date of data collection (MM/DD/YYYY) Transect #: Identifier for three individual transects established within each study site Plot #: Plot number assigned based on two sampling distances from the marsh edge (1 m or 10 m from the marsh edge) Littoraria irrorata: counts for periwinkle snails Geukensia demissa: counts for ribbed mussels Crassostrea virginica: counts for oysters Neritina usnea: counts for olive nerite snails Melampus bidentatus: counts for common marsh snails LSU/RCAT ID# for oil data: Internal sample identifier assigned by the analytical lab; oil data can be found in GRIIDC Unique Dataset Identifier (UDI) R4.x264.000:0056.
File: R1.x139.144-0021_RabalaisInvertebrateData_v1.xlsx Worksheet: Site Information Site: User-defined identifier assigned to field sites (GI*= W Barataria Bay, N of Grand isle; PS*= E Barataria, Bay Jimmy, Port Sulphur area; TB*= Terrebonne Bay) Hypothesized Site Exposure Type: User-defined classification of the site at the beginning of the project, in regards to possible Macondo oil exposure (unoiled or oiled). Transect #: Identifier for three individual transects established within each study site Distance from marsh edge (m): Distance from edge into marsh where samples were collected (1m = edge, 10 m = interior) LAT (decimal degrees): Latitude of the field site LONG (decimal degrees): Longitude of the field site Worksheet: Mussels and Snails Site: User-defined identifier assigned to field sites (GI*= W Barataria Bay, N of Grand isle; PS*= E Barataria, Bay Jimmy, Port Sulphur area; TB*= Terrebonne Bay) Date collected: Date of data collection (MM/DD/YYYY) Transect #: Identifier for three individual transects established within each study site Distance from marsh edge (m): Distance from edge into marsh where samples were collected (1m = edge, 10 m = interior) Snail Abundance: Number of individuals found per 0.5 meter quadrat Mussel Abundance: Number of individuals found per 0.5 meter quadrat Worksheet: Hydrocarbon Data Site: User-defined identifier assigned to field sites (GI*= W Barataria Bay, N of Grand isle; PS*= E Barataria, Bay Jimmy, Port Sulphur area; TB*= Terrebonne Bay) Date collected: Date of data collection (MM/DD/YYYY) Transect #: Identifier for three individual transects established within each study site Distance from marsh edge (m): Distance from edge into marsh where samples were collected (1m = edge, 10 m = interior) Total Alkanes (ug/L): Concentration of Alkane hydrocarbons in sediment samples collected in the same area as the mussels and snails, expressed in micrograms per liter Total Aromatics (ng/L): Concentration of Aromatic hydrocarbons in sediment samples collected in the same area as the mussels and snails, expressed in nanograms per liter.
Methods:
Snails, oysters, and mussels were collected at four field sites within Terrebonne Bay, five sites around Grand Isle, and four sites in the Port Sulphur area. Organisms were collected from within 0.5 x 0.5 m (0.25 m2) quadrats placed 1 and 10 m from the marsh edge at three transects perpendicular to shore, in oiled-unoiled pairs per region. Snails were found on the sediment surface or on Spartina stems. Very small snails (<6 mm) hidden in the folds of Spartina stems were generally ignored, i.e. not every Spartina leaf was unfolded to systematically look for these. Mussels were partially buried and attached to Spartina and Juncus roots & stems and some digging and cutting with a knife or trowel was required for collection. In some cases, oysters (Crassostrea virginica) or mixed oyster-mussel clumps were collected, and these were handled the same as mussels. Mussels and snails were placed in separate labeled zip-loc bags or whirl-paks, kept on ice, and then transported to the laboratory for counting.
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