NOAA ocean explorers used an advanced multibeam sonar mapping system on NOAA Ship Okeanos Explorer in November to discover and map the first deep water gas seeps found off the U.S. Atlantic Coast north of Cape Hatteras.

The seeps were found at water depths greater than 3,300 feet. Based on preliminary information, scientists believe the seeps are likely emitting methane gas.

Locating seeps with this advanced technology will expand opportunities for researchers to study how seeps in the deep ocean environment affect ocean chemistry. NOAA’s use of advanced technology to discover seeps will benefit other agencies, including the U.S. Geological Survey.

The seeps were mapped between November 2^nd to November 20th 2012 at three different locations with water depths of 3,300 to 5,250 feet. Approximately 25 distinct seafloor gas seeps were identified based on plumes rising into the water column as high as 3,600 feet. The sites are between 91 and 101 miles off shore, with one site east of Cape Henry, Va., and two sites south and southeast of Nantucket Island, Mass.

Single beam sonar systems have been used extensively to map gas seeps but do not provide as much coverage as typically collected by multibeam systems. Multi-beam sonar obtains information from a fan-shape of beams, mapping a wider area more quickly and efficiently. Most multibeam sonars cannot process sonar signals from water-column seeps but the multibeam sonar on Okeanos Explorer is one of the few that is specially configured to do so.

NOAA’s Office of Ocean Exploration and Research is the only federal program that systematically explores Earth’s largely unknown ocean. The 224-ft. NOAA Ship Okeanos Explorer, homeported in Davisville, R.I., is operated by NOAA’s Office of Marine and Aviation Operations, and NOAA’s Office of Ocean Exploration and Research operates the cutting-edge ocean exploration systems on the vessel and ashore.

NOAA’s mission is to understand and predict changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.

Source:
NOAA
Image: NOAA