Abstract:

Laboratory analysis of Lander Deployed MIMOSA (MIcrobial Methane Observatory for Seafloor Analysis) samples. MIMOSA experiments use OsmoSamplers to continuously collect long term, in-situ samples for sulfate and chloride concentrations. The samplers are connected to PVC chambers (~100mL volume) that are packed with either control mud from the site (referred to as control chamber), or with a mixture of control mud and oil (referred to as oil chamber). Samplers and chambers are placed on benthic landers and remain at the field site from October 2013 to March 2014 at GC600. The samplers slowly collect fluids from inside the chambers over this time frame and store the samples in long, thin bore tubing for analysis on shore. Once recovered, the samples were analyzed for sulfate, chloride, methane, major ion (strontium, lithium, sulfur, calcium, magnesium, potassium, boron, manganese, iron, silica), and trace metal (cadmium, lead, uranium, vanadium, chromium, cobalt, nickel, copper, rubidium, molybdenum, cesium, barium) concentrations every 4-5 days. Stable carbon isotope ratios of methane carbon were also measured.

Suggested Citation:

Laura Lapham. 2016. Microbial Methane Observatory for Seafloor Analysis (MIMOSA) Geochemical Data from a Natural Seep Site in the Gulf of Mexico, October 2013 to March 2014. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7M043FK

Publications:

Orcutt, B. N., Lapham, L. L., Delaney, J., Sarode, N., Marshall, K. S., Whaley-Martin, K. J., … Girguis, P. R. (2017). Microbial response to oil enrichment in Gulf of Mexico sediment measured using a novel long-term benthic lander system. Elem Sci Anth, 5(0), 18. doi:10.1525/elementa.129

Purpose:

To determine rates of sulfate depletion and methane increase over time when oil is present in chambers. Also to determine concentrations of major ions and trace metals over time.

Data Parameters and Units:

date (mm/dd/yyyy); CH4 (nM); d13C-CH4 (0/00); date (mm/dd/yyyy); Cl (mM); SO4 (mM); Cl/SO4 (ratio); date (mm/dd/yyyy); strontium (Sr, umol/kg); lithium (Li, umol/kg); sulfur (S, umol/kg); calcium (Ca, umol/kg); magnesium (Mg, umol/kg); potassium (K, umol/kg); boron (B, umol/kg); manganese (Mn, umol/kg); iron (Fe, umol/kg); silica (Si, umol/kg); date (mm/dd/yyyy); cadmium (Cd, nM); lead (Pb, nM); uranium (U, nM); vanadium (V, nM); chromium (Cr, nM); cobalt (Co, nM); nickel (Ni, nM); copper (Cu, nM); rubidium (Ru, nM); molybdenum (Mo, nM); cesium (Cs, nM); barium (Ba, nM)

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