Macondo Oil Spill Assessment at Woolsey Mound Continues

MMRI continues to be very active in assessing effects of the oil spill in the Gulf. Woolsey Mound is a dynamic site with active hydrocarbon venting, gas hydrate accumulation and diverse habitats with unique biota, just 10 nautical miles from site of the April Transoceanic/BP catastrophe. Since the Gulf of Mexico Hydrates Research Consortium has been conducting geological, geochemical, geophysical and biological research projects at MC118 for over five years, Woolsey Mound provides a perfect site to evaluate the potential effects of overprinting of the oil spill on a natural seep in the Gulf of Mexico.

MMRI has been engaged in new sensor development for several years as part of the Seafloor Observatory project and this work proved invaluable for assessing the impact of the oil spill on the site. In June, MMRI used several of these instruments to identify new plumes of methane present in the deep marine environment, well below the surface accumulations that were widely documented. The deep-water plumes, however, went undetected until our work in June. A task was added to our September schedule to follow up on these earlier assessments and this work indicates that the plumes are no longer present in the area. Attention has since turned from the water column to assessing the potential for overprinting on the seafloor. In September we collected multiple sets of push cores from two different areas with our Station Service Device (SSD), MMRI's custom designed and built Remotely Operated Vehicle. Preliminary laboratory results indicate all of these cores have significant amounts of petroleum hydrocarbons in them. Push core VII contains black material with fine flocculated material above. Preliminary analysis of total petroleum hydrocarbon of this material is 43 ug/g. Push Core VI has several centimeters of reddish brown material on top of the typical lighter gray marine sediments. The reddish brown material has a total petroleum hydrocarbons concentration of 57 ug/g. Further testing is underway to finger print the source of the oil and, until that is completed, little is known about the provenance of the hydrocarbons.

Push Cores taken at MC118

Interest in Woolsey Mound has intensified recently, in part, because it is the only BOEMRE-designated research reserve in the Gulf of Mexico and, due to the efforts of the Consortium, has extensive, pre-spill data. Woolsey Mound has been included in the cruise plans for two high profile cruises later this fall. Dr. Chuck Fisher, Chief scientist on the BOEMRE/NOAA-funded Lophelia II Ron Brown /Jason II cruise to evaluate the impact of the spill on deep-marine corals, has added Woolsey Mound to his site visits list and MMRI visiting scholar, Michela Ingrassia, to his scientific crew after Michela notified him of several examples of deep-sea corals at the site. Dr. Samantha Joye will be diving the Alvin deep-diving submarine at MC118 for discrete sample collection as part of her ongoing spill-response efforts. MMRI and others will be taking part in a special session of the American Geophysical Union’s annual meeting to present the results of oil spill related work in the Gulf.

(October 2010)