Abstract High salinities and high temperatures at the seafloor record the upward flow of water and hydrocarbons from depth at natural vents in the deepwater Gulf of Mexico. We present a multiphase heat- and solute-transport model, in which water supplied from depth transports heat and salt, and hydrocarbon transports heat. We show that there is a unique water and hydrocarbon flux that simulates the observed salinity and temperature. We estimate the hydrocarbon flux to be 3.2 – 15 × 10 4 t yr − 1 and 1.8 – 8.0 × 10 4 t yr − 1 from two vents at lease blocks MC852/853 and GB425. These fluxes are 1–4 orders of magnitude greater than previous estimates from individual deepwater vents. If these results are extrapolated to the entire Gulf of Mexico, then we estimate the regional hydrocarbon flux to be at least 100× greater than previous estimates and 14–120% of the hydrocarbon flux from the Macondo oil spill. Large natural seepage may inoculate marine basins such as the Gulf of Mexico from oil spills like the 2010 Deepwater Horizon blowout by sustaining populations of hydrocarbon-degrading bacteria.

Hydrocarbon flux from natural deepwater Gulf of Mexico vents

Marine seepage variability and its impact on evaluating the surface migrated hydrocarbon seep signal

The Gulf of Mexico Research Consortium (CIGoM) was founded in 2015 as a consortium of scientific research and consulting services, specializing in multidisciplinary projects related to the potential environmental impacts of natural and human-induced oil spills in marine ecosystems, to understand and act in case of possible large-scale oil spills in the Gulf of Mexico. The consortium is composed of more than 300 specialized researchers trained at the most recognized Mexican institutions. Among the main lines of interest are, to develop the first baseline of the bacterial community inhabiting the Gulf of Mexico, to investigate the natural degradation of hydrocarbons by bacterial communities and microbial consortia and the identification and characterization of industrially relevant enzymes. In this manuscript, we present a review of the taxonomy found in samples of water and sediments taken from the Perdido Fold Belt (northwest), Campeche Knolls (southeast) and sediments of the southwest region of the Gulf of Mexico. We report here some efforts of bioprospecting of strains and enzymes with hydrocarbon degradation capacity, using by sequence and function screening methodologies; we also report the construction and exploration of metagenomic libraries using metagenomic DNA from consortia or environmental samples collected off the coast of Tamaulipas in the Perdido Escarpment area, at the northwest of the Gulf of Mexico, and from sediment samples from the southwest of the Gulf of Mexico on the coast of Campeche, looking for enzymes with high biotechnological potential as lipases and dioxygenases with novel characteristics and specific hydrocarbon-degrading strains that could be used in bioremediation processes by immobilization techniques or to be used as biosensors and mesocosms assays.

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Bacteria From the Southern Gulf of Mexico: Baseline, Diversity, Hydrocarbon-Degrading Potential and Future Applications

Organic geochemistry of hydrocarbon seeps associated with sulfurous spring water, western Iraq: Biodegradation, source rock and sedimentary environment

. In this study, we present a novel approach for assessing nearshore seepage atmospheric emissions through modeling of air quality station data, specifically, a Gaussian plume inversion model. Three decades of air quality station meteorology and total hydrocarbon concentration, THC, data were analysed to study emissions from the Coal Oil Point marine seep field offshore California. THC in the seep field directions was significantly elevated and Gaussian with respect to wind direction, θ. An inversion model of the seep field anomaly, THC’(θ), derived atmospheric emissions. The model inversion is for the far field, which was satisfied by gridding the sonar seepage and treating each grid cell as a separate Gaussian plume. This assumption was validated by offshore in situ offshore data that showed major seep area plumes were Gaussian. Plume air sample THC was 85 % methane, CH4, and 20 % carbon dioxide, CO2, similar to seabed composition, demonstrating efficient vertical plume transport of dissolved seep gases. Air samples also measured atmospheric alkane plume composition. The inversion model used observed winds and derived the three-decade-average (1990–2021) field-wide atmospheric emissions of 83,500 ± 12,000 m3 THC day−1. Based on a 50:50 air to seawater partitioning, this implies seabed emissions of 167,000 m3 THC dy−1. Based on atmospheric plume composition, C1-C6 alkane emissions were 19, 1.3, 2.5, 2.2, 1.1, and 0.15 Gg yr−1, respectively. The approach can be extended to derive emissions from other dispersed sources such as landfills, industrial sites, or terrestrial seepage if source locations are constrained spatially.

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M. Woosley

Papers

Hydrocarbon migration pathway and methane budget for a Gulf of Mexico natural seep site: Green Canyon 600