The National Oceanic and Atmospheric Administration (NOAA) is carrying out a series of survey voyages to map the seabed off the Aleutian Islands and, in particular, the Aleutian Trench – an underwater depression stretching from Russia to the south Kenai Peninsula. During the first voyage, the research vessel Okeanos Explorer identified previously unknown gas leaks close to the seabed. NOAA believes that the “noodle-like” lines on the sonar images taken by the ship are the result of sonar signals being reflected off bubbles near the sea floor, indicating the presence of an undiscovered underwater gas leak.
The seabed locations of gas leaks are usually rich in marine life that exist on symbiotic relationships with the bacteria that process hydrogen sulfide. NOAA believes that spills occur when a large reservoir of gas is compressed from below by tectonic activity. The six survey voyages, which run through to September, form part of a programme targeted at the Aleutian Trench and covering a range of unexplored areas, including visits to seamounts, deep sea coral and sponge ecosystems, and exploration of hydrothermal vents.