Mapping Gas Seeps with the Deepwater Multibeam Echosounder on Okeanos Explorer

The Gulf of Mexico has long been known to contain large reservoirs of oil and gas. Some of these hydrocarbons make their way up through faults to the seabed surface (Roberts and Carney, 1997), providing an energy source for chemosynthetic communities (Fisher et al., 2007). Methane bubbles at these sites are sometimes released into the sea-water where they dissolve or, occasionally, rise to the sea surface and into the atmosphere (MacDonald et al., 2002). Detecting the presence of gas seeps and mapping their locations are critical steps toward refining our understanding of the complex geological and biological processes occurring in the deep Gulf of Mexico, as well as our understanding of background conditions in light of events such as the Deepwater Horizon spill.