Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG)

Dr. Ray Highsmith (1941-2013) at the University of Mississippi was awarded an RFP-I grant at $20,250,000 to lead the GoMRI Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG) Consortium that consisted of 14 collaborative institutions and 203 research team members (including students). After Dr. Highsmith's passing in 2013, Dr. Alice Clark (also at the University of Mississippi) took over as Consortium Director for 8 months. Dr. Geoff Wheat (also at the University of Mississippi) then took over as Consortium Director until completion of the project. The goals of ECOGIG were to understand the impacts of natural seepage versus that of abrupt, large hydrocarbon inputs on coupled benthic-pelagic processes in deep water ecosystems and to chart long-term effects and mechanisms of ecosystem recovery from the DWH accident. Starting with quantifications of the physical mechanisms that distribute and redistribute oil within the coupled benthic-pelagic system, ECOGIG researchers determined the impact of oil on the pelagic food web, including microorganisms, phytoplankton, grazers, ichthyoplankton and coral, by evaluating its toxicity, biodegradation, and trophic transfer. Outreach Over its award period (3 years, plus a 12-month no-cost extension), ECOGIG organized approximately 425 outreach activities or products, including but not limited to: Developing a research video series (http://ecogig.org/galleries/videos), which included over a dozen short videos in three targeted series, produced by Gary Finch Productions, LLC, in partnership with the Mississippi-Alabama Sea Grant Consortium (MASGC). Developing a fourth grade STEM activity coordinated by the University of Mississippi in classrooms in northern Mississippi, at several Boys and Girls Clubs in southern Mississippi, and at the Infinity Space Center. This activity engaged more than 2000 4th grade students from Mississippi and Louisiana. Developing and then conducting annually its 'Science at the Stadium' activity, during which ECOGIG engaged the public at UGA and UM football games. Developing and implementing Seafloor Science and ROV Camp, a week-long, STEM day camp for 6-8th graders. Creating and displaying an exhibit, titled 'Living Life in the Extreme: Deep Sea Habitats and Exploring Them,' on the UGA campus focused on extreme environments in the deep sea and the need to explore them for gaining a better understanding of the effect climate change and other disturbances, like deepwater oil spills, have on these communities. Research Highlights As of December 31st, 2015, ECOGIG research, which entailed 22 research cruises or expeditions, resulted in 66 peer-reviewed publications, more than 220 scientific presentations and 139 datasets being submitted to the GoMRI Information and Data Cooperative (GRIIDC), which are/will be available to the public. ECOGIG engaged 106 students over its award period. Significant outcomes of ECOGIG research according to GoMRI Research Theme are highlighted below. Theme 1: Physical Processes Research from ECOGIG improved the understanding of both horizontal and vertical transport and mixing mechanisms at the ocean surface and, more importantly, along the Gulf of Mexico continental slope. They found that submesoscale instabilities at the ocean surface and at depth are a source of significant variability and trapping of material released at the base/within the mixed layer or close to the sea floor (the vorticity field along the continental slope below 500m is strongly ageostrophic and the Rossby number is often >1). Theme 2: Chemical/Biological Processes Researchers from ECOGIG made in situ time-series methane measurements at GC600 hydrocarbon seep sites during April 2014 using a prototype laser sensor (developed in collaboration with a German company) deployed by the Alvin research submarine. Methane concentrations 1000 times greater than background sites occurred immediately adjacent to gas vents. This data collection represents the first continuous in situ methane measurements at natural hydrocarbon seeps available anywhere in the world. Continuous current speed and DO measurements were utilized by ECOGIG researchers to generate sediment total oxygen utilization (TOU) measurements at MC118 for periods up to 160 days. The influence of large-scale water mass mixing and meter-scale sea floor topography on ambient DO concentrations was determined, enabling future quantification of local influences on water column oxygenation. ECOGIG laboratory researchers demonstrated that oil-derived marine snow forms a hotspot of heterotrophic microbial activity and oil degradation. Marine snow enriched with carbon from oil exhibited strongly elevated hydrolysis rates for polymeric carbohydrates; parallel 16S ribosomal RNA gene sequencing has shown that the microbial community of these oil snow particles contains numerous specialized oil-degrading bacteria (Cycloclasticus), heterotrophic bacteria that produce hydrocarbon-emulsifying exopolymers (Marinobacter; Halomonas), and members of the marine Roseobacter cluster that collaborators in Germany (Oldenburg University) have recently isolated on DWH surface oil. All of these organisms are likely primary oil degraders. The combined functional and taxonomic evidence shows that marine snow particles that contain decomposed oil components are formed as a key natural response to hydrocarbon pollution; they are our strongest microbial candidates for degrading and re-mineralizing petroleum hydrocarbons near the sea surface and in the water column. Ultimately, these marine snow particles are the most likely candidates for transporting oil-degrading bacteria to the sea floor where they accumulate. A focused series of hydrocasts were conducted inside and just outside of plumes of bubbles associated with natural seeps at both shallow (GC185, GC233) and deep (GC600) seeps. Nutrient measurements at sea show interesting but variable contrasts between the in/out of plume casts, suggesting a seep-specific impact on the nutrient budgets of the overlying waters. Experimental measurements of dinitrogen fixation in deep waters collected inside and just outside of bubble plumes show up to a three-fold enhancement of dinitrogen fixation inside the plume. These results imply that seeps can directly alter nutrient stocks in deep water and that injection of CH4 into deep water can affect the biogeochemical activity of plankton on the short temporal scales associated with active bubble plumes. ECOGIG researchers measured rates of methane oxidation in and out of plumes at GC600. Rates of methane oxidation are up to five times higher inside the plumes, where methane concentrations are substantially elevated above background, compared to outside plumes where methane concentrations are essentially background (2–5 nM). ECOGIG researchers conducted long-term, continuous experiments on the sea floor. These experiments have produced the first estimates of the rate at which oil degrades at the bottom of the Gulf and the first assessment of the environmental factors that limit its degradation. Theme 3: Environmental Effects ECOGIG reported that deep-water corals are ecosystem-level indicators of acute and chronic hydrocarbon exposure. Some of the heavily impacted sites continued to decline in health and will likely take hundreds of years to recover, if they recover at all. At some of the lightly impacted sites, some of the corals are beginning to regrow some of their branches and may eventually return to the state they were in prior to the spill, although this will also likely take decades to centuries. The loss of these corals has implications for the long-term recovery of the deep-sea ecosystem. They host a community of other species that rely on them for shelter, feeding, and nursery grounds. ECOGIG researchers worked on identifying different potential pathways of how decomposing oil is transported from the water to the sea floor. A fraction of the spilled oil led to the formation of microbial, mucus-rich marine snow. The formation of this marine snow due to the bacterial response to weathered oil had not been observed before. This work also showed that oil could be incorporated into phytoplankton aggregates. The different types of marine snow, as well as oil mineral aggregations, were heavy enough to sink at significant speeds and transfer decomposing oil to the sea floor, where the hydrocarbon-containing marine snow impacted corals, fish, and other sea floor organisms. The efficiency of these combined transport mechanisms was unexpected. Theme 4: Technology Developments ECOGIG tested and deployed advanced prototype instruments for time series chemical measurements, including ambient methane concentration and sediment oxygen demand, which offer improved detection methods for baseline characterization and monitoring.