Abstract:
At locations surrounding the Deepwater Horizon drilling site, box core samples and Shipek grab samples were collected for subsurface meiofauna and sediment analysis during the October-November 2012 NOAA Gordon Gunter cruise. This dataset contains sediment and meiofauna data comparing 5 box core sediment collections with 5 shipek sediment collections. Nematode and copepod diversity from the box core sites is provided. The dataset supports the publication Stephen C. Landers et al, Nematode and copepod diversity (2012) from Louisiana near the Deepwater Horizon oil spill, Proceedings of the Biological Society of Washington 127(1):47-57. 2014 doi: http://dx.doi.org/10.2988/0006-324X-127.1.47
Suggested Citation:
Landers, Stephen. 2014. Dataset for: Nematode and copepod diversity (2012) from Louisiana near the Deepwater Horizon oil spill. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7N877Q1
Purpose:
The purposes of this study were to: 1) obtain a taxonomic analysis of two dominant meiofauna groups, nematoda and copepoda, 2) statistically analyze animal densities and sediment characteristics, and 3) compare the efficiencies of two different collection devices.
Data Parameters and Units:
Box Core verses Shipex Grab: Sample number, vessel, Cruise, Station Meiofauna (i.e. copepods and nematodes) [copepods: Ameirridae, Cletodidae, Ectinosomatidae, Miraciidae, Normanellidae, Paramesochridae] [nematodes: Aegialoalaimidae, Axonolaimidae, Ceramonematidae, Chromadoridae, Comesomatidae, Cyatholaimidae, Desmoscolecidae, Desmodoridae, Diplopeltidae, Draconematidae, Enchelidiidae, Enoplidae, Epsilonematidae, Ironidae, Leptolaimidae, Linhomoeidae, Microlaimidae, Monhysteridae, Oxystominidae, Selachinematidae, Taravaiidae, Xyalidae, Pandolaimidae, Selachinematidae, Unident] (average number of individuals per 15.19 cm^2) Polychaeta (average number of individuals per 15.19 cm^2) Kinorhyncha (average number of individuals per 15.19 cm^2) PAH's concentrations (ppb, parts per billion) Metals concentrations [Ni, V] (mg/kg) raw soil metals data: Sample, Lab ID, Field ID, Analyte, Dilution Factor, Measured Concentration (mg/kg), Blank-Corrected Concentration (mg/kg), MDL (mg/kg), Batch number N:C ratio Organic carbon (% of total sediment) Time (MM/DD/YY hh:mm) Latitude (decimal degrees) Longitude (decimal degrees) Depth (meters) Temperature (degrees Celsius) Oxygen (mg) Salinity (psu)
Methods:
Sediment samples were collected using a Shipek® grab sampler and a box corer aboard the NOAA ship Gordon Gunter at 5 locations near the DHOS site. Each site was sampled twice, one time with each collection device. 30 subcores were obtained for meiofauna and remaining sediment was analyzed for metals and PAHs. Meiofauna samples were fixed in 10% formalin, sieved, and centrifuged with Ludox® to concentrate the meiofauna. Meiofauna were counted and identified under a stereomicroscope at Troy University, according to Higgins and Thiel (1988) and Giere (2008). The first 100 nematodes from the 5 box core sites were mounted in glycerin, identified to genus and categorized by feeding group classification. Copepods from the 5 box core sites were mounted whole or dissected in polyvinyl lactophenol for ID to genus/species level. Sediment PAHs were determined using Soxhlet extraction with methylene chloride (EPA 3540C) and a Shimadzu GCMS. Metals were determined by two methods: 1) samples were digested with nitric acid, oxidized with hydrogen peroxide, diluted with sulfuric acid and submitted to Southern Environmental Testing, Inc. for ICP anaylsis using EPA-600/4-79-020, and 2) samples were analyzed at the Central Analytical Instruments Research Laboratory at Louisiana State University using EPA ICP method 200.7. All continental shelf sediments were extracted for polycyclic aromatic hydrocarbons (PAH) analysis with the best available quality assurance (QA) and quality control (QC) as followings: Sediment extraction: Each sediment was extracted using a Soxhlex extraction apparatus with dimethylene chloride (DCM). Protocol is adapted from the EPA method 3540c. Each sediment was divided into three sub-samples (named replicate 1, replicate 2 and spike). Three sets of Soxhlet extraction system were used simultaneously for each sub-sample respectively. Each sub-sample is mixed with sodium sulfate (sediment/sodium sulfate ratio about 1/2) to remove sediment moisture for maximum performance of extraction by DCM. The spike sub-sample was amended with 1 mL 1 ppm PAH standard for calculation of extraction recovery rate each time. The extraction system is equipped with a temperature controlled water circulation system for condenser and concentrator to minimize temperature variations in the laboratory during the 20-hour extraction period. Final volume of the extract is 1 mL, representing approximately 10 times of original PAH concentration in the sediment. The sediment dry weight is determined and all PAH results are express in dry weight basis. PAHs and their reference standards: The following 27 PAHs are quantified for each sediment. Since no particular target PAH is pre-determined, a broad spectrum PAH components are included to capture as much information (both petrogenic and pyrogenic PAHs) as possible. The standard is purchased from Absolute Standards, Inc. (http://www.absolutestandards.com/). Benzo(e)pyrene Biphenyl Dibenzofuran Dibenzothiophene 2,6-Dimethylnaphthalene 1-Methylnaphthalene 2-Methylnaphthalene 1-Methylphenanthrene 2,3,5-Trimethylnaphthalene Perylene Acenaphthene Acenaphthylene Anthracene Benzo(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(g,h,i)perylene Carbazole Chrysene Dibenzo(a,h)anthracene Fluoranthene Fluorene Indeno(1,2,3-cd)pyrene Naphthalene Phenanthrene Pyrene Analytical instrument: The laboratory at Troy University is equipped with a Schimadzu GC/MS (GC-2010-mass spectrometry) for the PAH analysis. The GC/MS has been calibrated for petroleum hydrocarbon analysis, including capillary column selection, flow control and temperature programming. For each analysis, a batch file is generated to run sample in the following sequence: DCM/PAH standard/Replicate 1/Replicate 2/Spike/Replicate 2/Replicate 1/DCM This batch analysis (8 runs x 1 hour/each run) ensures that the two replicate sub-samples run twice with either standard or spike (with 1 mL standard in it) ahead to calibrate the retention time for each PAH component. The solvent run before and after the samples ensures the GC/MS in the best condition for the sample analysis. Calculation: PAH components are quantified from the GC/MS data analysis. Results represent the means of four analyses (two replicates x two runs). Extraction recovery rate is determined by the recovery of added standard in the spike. Results are reported after correction according to the determined recovery rate each time. The final results are reported in ppb based on the dry weight of the sediment. External reference laboratory: For further QA/QC, 4 sediment samples will be randomly selected for analysis of PAHs by an external reference laboratory. Central Analytical Instruments Research Laboratory 312 M.B. Sturgis Hall Louisiana State University Baton Rouge, LA 70803
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