A seafloor observatory to monitor a cold seep in the Gulf of Mexico

Cold seeps occur widely on the continental shelf and slope of the northern Gulf of Mexico. Typically, they are located where faults intersect the sea floor and act as conduits for hydrocarbon fluids migrating upward from deep reservoirs. The fluids are sources of energy for microbes which proliferate in the vicinity of the seeps. The microbes precipitate a wide range of minerals that accumulate to form mounds which surround the seeps. The microbes also secrete biosurfactants that enhance the formation of natural gas hydrates (Rogers and Lee, 2001; Rogers et al., 2002; Rogers et al., 2003). Therefore, in water depths greater than about 450m, the mounds often contain hydrates. The photograph in fig.1 shows such a mound. Its vicinity is littered with mussel shells and other chemosynthetic detritus. Parts of the mound's surface are covered by orange-colored microbial mats. The white material outcropping from the lower part of the mound is gas hydrate.