Abstract:
This dataset contains values for chemical and microbial parameters including sediment porewater concentrations of hydrogen sulfide, oxygen, Eh, and pH; total petroleum hydrocarbons; and anaerobic/aerobic soil microbial communities from four wetland locations that were oiled from the Deepwater Horizon Oil Blowout in Mississippi and Louisiana: Salt Pan Island (SP), Marsh Point (MP), Cat Island (CI), and Skiff Island (SI). In MP, temporal studies were conducted for sediment porewaters over three years (2010-2012). At each marsh, 20-cm deep soil cores were collected at locations had observable oiling. Cores were profiled at 1cm increments for sediment porewaters measured using microelectrodes and then sliced into 2-cm sections under anaerobic conditions. Each 2-cm section was analyzed for TPH and aerobic/anaerobic microbial communities. At all locations water column temperature, dissolved oxygen, and salinity was recorded. This dataset is also registered with GRIIDC as Y1.x103.000:0004.
Suggested Citation:
Karen McNeal. 2015. Sedimentary Pore-Water pH, Redox Potential, and Concentrations of Hydrogen Sulfide, Oxygen, and Total Petroleum Hydrocarbons, and Anaerobic and Aerobic Microbial Activity from 4 Northern Gulf of Mexico Sites 2010 to 2012. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N77S7M5V
Purpose:
This study intended to allow the identification of ‘hotspots’ of marsh degradation and the extent of recovery (if any) post Deepwater Horizon Oil Spill. The overall goal of the proposed research was to quantify and map the ecological impact of the oil spill on the photosynthetic activity, physiological status, and primarily productivity of the coastal salt marshes to facilitate the prioritization of future restoration actions. The specific questions to be answered through study were: What is the degree of damage and extent of recovery in the spill impacted marsh habitats? And Is the damage due to sedimentary biogeochemical processes resulting from the degradation of the oil and increased microbial production of reduced chemical species such as sulfide?
Data Parameters and Units:
Coordinate Worksheet: Site = site name and abbreviation, Date = dates samples (M, DD, YYYY), Lat = latitude of sample site in degrees minutes seconds, Long = longitude of sample site in degrees minutes seconds Location Parameters Worksheet: Location = sample site name, Temperature (°C) = temperature at sample site in degrees Celsius, DO (mg/L) = dissolved oxygen in milligrams per liter at the sample site, Salinity (‰) = salinity at sample site in parts per thousand, Tidal Flux (ft) = tidal flux at sample site in feet Skiff Island Worksheet: Sediment depth (um) = depth of sediment sample in micrometers at Skiff Island site, H2S Concentration (umol/l) = sediment concentration of hydrogen sulfide in micromoles per liter in sediment from Skiff Island site, O2 Concentration (umol/l) = sediment concentration of oxygen in micromoles per liter in sediment from Skiff Island site, pH = pH of sediment from Skiff Island site, Redox Potential (mV) = reduction potential of sediment from Skiff Island site in millivolts Saltpan Worksheet: Sediment depth (um) = depth of sediment sample in micrometers at Saltpan site, H2S Concentration (umol/l) = sediment concentration of hydrogen sulfide in micromoles per liter in sediment from Saltpan site; Signal = hydrogen sulfide signal in millivolts for sediment from given depth at Saltpan site; O2 Concentration (umol/l) = sediment concentration of oxygen in micromoles per liter in sediment from Saltpan site, pH = pH of sediment from Saltpan site, Redox Potential (mV) = reduction potential of sediment from Saltpan site in millivolts Marsh Point Worksheet: Sediment depth (um) = depth of sediment sample in micrometers at Marsh Point site, H2S Concentration (umol/l) = sediment concentration of hydrogen sulfide in micromoles per liter in sediment from Marsh Point site; Signal = hydrogen sulfide signal in millivolts from sediment at given depth at Marsh Point site; O2 Concentration (umol/l) = sediment concentration of oxygen in micromoles per liter in sediment from Marsh Point site, pH = pH of sediment from Marsh Point site, Redox Potential (mV) = reduction potential of sediment from Marsh Point site in millivolts Cat Island: Sediment depth (um) = depth of sediment sample in micrometers at Cat Island site, H2S Concentration (umol/l) = sediment concentration of hydrogen sulfide in micromoles per liter in sediment from Cat Island site, O2 Concentration (umol/l) = sediment concentration of oxygen in micromoles per liter in sediment from Cat Island site, pH = pH of sediment from Cat Island site, Redox Potential (mV) = reduction potential of sediment from Cat Island site in millivolts Site Graphs Worksheet: 5 plots. Plot 1: Hydrogen sulfide signal with depth for 4 sites; Plot 2: Oxygen concentration with depth for 4 sites; Plot 3: pH with depth between for four sites; Plot 4: Redox Potential with Depth for four sites; Plot 5: Hydrogen sulfide concentration with depth for 4 sites Total Petroleum Hydrocarbons Worksheet: Site = sample site and replicate identifier where SP = Saltpan MP = Marsh Point SI = Skiff Island and CI = Cat Island; Depth (cm) = depth of sediment sample analyzed for total petroleum hydrocarbons for site and replicate in centimeters; soil (g) = weight of sediment sample analyzed for total petroleum hydrocarbon for site and replicate in grams; (g/kgsed) = grams of total petroleum hydrocarbon per kilogram of sediment for analyzed sample; Ttl/site (g/kg) = sum of grams of total petroleum hydrocarbon per kilogram of sediment for all samples analyzed from a single replicate; Avg. Location (g/kg) = the average of the Ttl/site for all replicates collected at a single site location in grams per kilogram Sample Chromatogram Worksheet = image of a sample chromatogram from Cat Island site Biolog AN Plates Worksheet: This worksheet reports data from Biolog Anaerobic microplates. Site = site and replicate for each sample; Depth = depth of sample analyzed in centimeters; ACWD: August = Absorbance or Average Well Color Development; ACWD: September = Absorbance or Average Well Color Development EcoMicroplates Worksheet: This worksheet reports data from Aerobic and Anaerobic Biolog EcoPlates ™. Site = site and replicate number; Depth = depth of sediment analyzed; August Sampling ACWD Aerobic ECO = Absorbance or Average Well Color Development for sediments analyzed in an aerobic EcoPlate ; August Sampling ACWD Anaerobic ECO = Absorbance or Average Well Color Development for sediments analyzed in anaerobic EcoPlate; September sampling ACWD Aerobic ECO = Absorbance or Average Well Color Development for sediment sample analyzed in an aerobic EcoPlate; September sampling ACWD Anaerobic ECO = Absorbance or Average Well Color Development for sediment sample analyzed in anaerobic EcoPlate Plate Graphs Worksheet: 2 Plots comparing results of anaerobic and aerobic plots from 4 sites MP Temporal 2010 Worksheet: Results from preliminary work completed at Marsh Point in October 2010 (columns A to D) and November 2010 (Columns G-J) for different replicates. Column A= depth of sediment sampled in micrometers; Column B = average hydrogen sulfide concentration in micromoles per liter for sediment at given depth; Column C = depth of sediment sampled in micrometers; Column D = average oxygen concentration in micromoles per liter for sediment at given depth; Column G = depth of sediment sampled in micrometers; Column H = average hydrogen sulfide concentration in micromoles per liter for sediment at given depth; Column I = depth of sediment sampled in micrometers; Column J = average oxygen concentration in micromoles per liter for sediment sampled at given depth; Column M = depth that average was calculated for in micrometers; Column N = Average hydrogen sulfide concentration in micromoles per liter for samples collected in October and November 2010 for given depth; Column O = Average oxygen concentration in micromoles per liter for samples collected in October and November 2010 for given depth. MP Temporal 2011 Worksheet= Rows 1 to 51 report averages for Marsh Point from 2011 samples. Depth = depth of sediment sampled in micrometers; H2S = average hydrogen sulfide concentration in micromoles per liter for sediment samples collected in August and September 2011 at Marsh Point for given depth; O2 = average oxygen concentration in micromoles per liter for sediment samples collected in August and September 2011 for given depth; pH = average pH for sediment samples collected in August and September 2011 for given depth; Eh = average reduction potential reported in sediments samples in August and September 2011 for given depth. Rows 56 to 106 columns A to N are measurements taken at Marsh Point in August 2011. Rows 56 to 106 columns P to AC are measurements taken at Marsh Point in September 2011. Average = depth at which sediment was sampled in micrometers in August 2011; H2S Concentration (umol/l) = hydrogen sulfide concentration in micromoles per liter for sediment at given depth in August 2011; Signal = hydrogen sulfide signal in millivolts for sediment sampled from given depth in August 2011; O2 Average = depth at which sediment was sampled in August 2011; Concentration (umol/l) = concentration of oxygen in micromoles per liter at given depth in August 2011; pH Average = depth at which sediment was sampled in August 2011; pH = pH of sediment sampled at given depth in August 2011; RD Average = depth at which sediment was sampled in August 2011; Potential = reduction potential in millivolts of sediment sampled at given depth in August 2011. Marsh Point Average = depth at which sediment was sampled in micrometers in September 2011; H2S Concentration (umol/l) = concentration of hydrogen sulfide in micromoles per liter for sample from given depth in September 2011; O2 Average = depth at which sediment was sampled in micrometers in September 2011; Concentration (umol/l) = concentration of oxygen in micromoles per liter in sediment from given depth in September 2011;pH 3285 ; pH Average = depth at which sediment was sampled for pH measurements in September 2011; pH = pH for sediment for given depth in September 2011; RD Average = depth at which reduction potential was measured in September 2011; Potential = Reduction potential in millivolts of sediment sampled at given depth in September 2011. MP Temporal 2012 Worksheet: This worksheet contains data collected from Marsh Point in Month? 2012. H2S 2728; Column B = depth at which sediment was sampled in micrometers in 2012. H2S Concentration (umol/l) = hydrogen sulfide concentration in micromoles per liter at given depth; O2 9296; O2 = depth in micrometers at which oxygen concentration was sampled; Concentration (umol/l) = concentration of oxygen in micromoles per liter for sediment sampled at given depth; pH 3285; pH = depth at which sediment was sampled in micrometers; pH = pH of sediment sampled at given depth; RD 5361; Eh = depth at which sediment was sampled for reduction potential in micrometers; Potential = Reduction potential in millivolts of sediment sampled at given depth. Temporal Graphs Worksheet: This worksheet contains 2 graphs showing the trend in hydrogen sulfide and oxygen concentrations in Marsh Point samples collected from 2010 to 2012.
Methods:
Water quality measurements including dissolved oxygen (DO), temperature, and salinity were taken using a YSI 85 Handheld (Yellow Springs, Ohio). Cores at least 15 cm in depth, preferably with overlying water, were collected manually or by using a hand coring device Sediment cores were taken to a 10-15 cm depth using core liners 9 cm in diameter and ~30-35 cm in length. Cores were then transported to a field laboratory for electrode analysis. Electrode profiles were collected using the Unisense microelectrode profiling system, Sensor Trace Pro software. The cores were then refrigerated and transported back to Mississippi State University to be sliced under anaerobic conditions to preserve the biological community. The refrigerated core was sliced into five 2 cm subsections inside a nitrogen-filled glove bag. The 2 cm sub sections were placed inside whirl bags and refrigerated until analysis was completed for Biolog. Only the top 6 cm of samples was analyzed, so for each core there were three samples: 0-2 cm, 2-4 cm and 4-6 cm depth, zero being the surface. Samples were prepared following traditional Biolog procedures where the sample was diluted 1:1,000 and pipetted into 96 well plates. Plates were incubated for 96 hours with measurements taken in 24 hour increments. Plates were read using a Fisher Scientific Original Multiskan MCC and data generated was statistically analyzed. To determine if sites were contaminated, total petroleum hydrocarbons (TPH) were measured. Samples were prepared using a method for non-polar hydrocarbon extraction modified from EPA Method 1664 (1995), in which, non-polar hydrocarbons are extracted from five to ten grams of sediment. Sediments were weighed into 40 mL vials and 20 mL of methylene chloride was added. Samples were vortex mixed for one minute then placed in a sonicator for ten minutes. Samples were then poured through 20 g of anhydrous sodium sulfate and filtered into a 50 mL pre-weighed beaker. The filter and sodium sulfate was then rinsed with 20 mL of methylene chloride to wash out any sample still in the filter. Beakers were placed in a fume hood until the methylene chloride evaporated and beakers were weighed again in order to calculate residual oil in the beaker. After finding the difference in the pre- and post- weight of the beaker TPH was calculated by dividing the residual by the weight of sediment it was extracted from. In order to get a more precise measure of TPHs present in samples, gas chromatography-mass spectrometry (GC-MS) analysis was also done. Samples were extracted in the same way as for TPH however, after evaporation was complete, the residue left in the beaker was dissolved with 4 mL of methylene chloride. The ~1000- 2000 ppm concentrated sample was then transferred into a 4 mL vial to be kept until GC-MS analysis. For GC-MS analysis, 1μL of sample was run through a 30 meter Perkin- Elmer Elite 225 column. The column is a crossbond of 50% yanopropylmethyl and50% phenylmethyl polysiloxane with a 0.32 mm ID. The injector temperature was 300°C. The GC began at 100°C and temperature increased at 5°C per minute until reaching 250°C. Temperature was maintained at 250°C for twenty minutes. After analyzing 1μL of concentrated sample, the results were run through a library of compounds to identify compounds indicative of hydrocarbon contamination. Preliminary study method deviations - The focus of the preliminary study was to determine how sediment biogeochemistry differs at contaminated and non-contaminated sites at Marsh Point in Ocean Springs, Mississippi. In October and November of 2010, six cores were taken at a contaminated site and six cores were taken at a non-contaminated site, three cores in marsh grass and three cores in sediment. Cores were capped, sealed, and transported back to the field lab where they were analyzed for pore water oxygen (O2) and hydrogen sulfide (H2S) using microelectrodes. Once cores were transported to the field laboratory, cores were analyzed for pore water hydrogen sulfide (H2S) and oxygen (O2) using a microelectrode profiling system. One profiled core from each site was refrigerated and other cores were frozen and transported back to the laboratory at Mississippi State University for further analysis. In order to complete Biolog analysis the refrigerated 2 cm sub sections were used. To analyze October 2010 samples, one ECO Microplate was used for each 2 cm subsection. Anaerobic Biolog analysis was not conducted in October 2010, however, both aerobic and anaerobic Biolog analysis was completed for November 2010. One ECO MicroPlate was used to measure the aerobic community and two AN Microplates were used to measure the anaerobic community. Only one ECO plate was used because ECO plates have replication in the wells, however, two AN plates were used because anaerobic plates do not have replication in the wells. Spatial study method deviations - Cores were collected at four locations: Salt Pan Island, Marsh Point, and Cat Island, Mississippi and Skiff Island, Louisiana (Figure 2.1). At each location three sites were chosen and three cores were taken at each of the three sites; a total of nine cores were taken per location. Cores were only taken in marsh grasses. Travel time to Marsh Point from GCRL was less than 30 minutes so electrode profiling was done at the GCRL. Traveling time back to a field laboratory to do electrode analysis was too long to prevent the core from either getting disturbed or from altering its geochemical state for Saltpan Island, Cat Island, and Skiff Island. Therefore, electrode analysis equipment was set up on the beach at these locations for profiling in the field. Electrode data was collected using H2S, O2, Eh, and pH microelectrodes. Electrode analysis was done on only one core from each site totaling to three cores per location. The remaining two cores collected at each site were sliced in the field and frozen for hydrocarbon analysis. Biolog analysis was conducted using the refrigerated 2 cm subsections of sliced cores. For each 2 cm depth, two ECO plates were used and two AN plates were used. One ECO plate was incubated in aerobic conditions and the remaining ECO plate was incubated in anaerobic conditions in order to compare color development for the same carbon sources with replication. The two AN plates were incubated in anaerobic conditions in order to better measure the anaerobic community based on anaerobic media.
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