Natural hydrocarbon seepage in the southern Gulf of Mexico - Cruise No. M114 - February 12 - March 28, 2015 - Kingston (Jamaica) - Kingston (Jamaica) (English)

R/V METEOR Cruise M114 investigated seafloor manifestations related to asphalt deposits on top of submarine ridges and knolls known as salt diapirs in the Campeche Bay of the Gulf of Mexico. The cruise was extremely successful in discovering spectacular manifestations of hydrocarbon emissions at the seafloor at various sites on the salt diapirs. Leg 1 focused on locating and mapping of hydrocarbon seeps by combining ship-based hydroacoustics, deep-towed sidescan sonar, and autonomous underwater vehicle (AUV) SEAL 5000 hydroacoustics whereas Leg 2 focused on observing and sampling of the seeps using the remotely operated vehicle (ROV QUEST 4000m). We found numerous gas bubble emissions at knolls and ridges in the western and northern part of the study area. A ridge was termed UNAM Ridge after discovery of prominent hydrocarbon seepage with amazing chemosynthetic communities. We acquired ultra-high morphological charts of hydrocarbon seeps and asphalt deposits at the three knolls termed Chapopote, Mictlan, and Tsanyao Yang. We discovered extensive asphalt deposits with spectacular flow formations at Chapopote and Mictlan Knoll. We successfully sampled these asphalt deposits for further analyses onshore. We documented vigorous emission of gaseous hydrocarbons and massive gas hydrate outcropping at the seafloor at Tsanyao Yang Knoll at water depths of 3400 m. We found that heavy oil seepage as well as gaseous hydrocarbon seepages provide the basis for extensive chemosynthetic life at the seafloor.