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Voyage to the Bottom of the Sea

NOAA Scientists Continue Mapping the Sea Floor in U.S. Virgin Islands

Boulder brain coral off the southwest coast of St. Thomas, U.S. Virgin Islands.

Boulder brain coral off the southwest coast of St. Thomas, U.S. Virgin Islands. Red lights from the ROV shining on the coral help scientists estimate its size.

High resolution (Credit: NOAA)

How do we choose which areas of the ocean to protect? And, which areas require more protection than others?

Well, scientists from NOAA’s Centers for Coastal Ocean Science are on a research expedition in the U.S. Caribbean to gather data that will help answer these and many other questions about the state of the sea floor.

A team of 21 researchers are aboard the NOAA Ship Nancy Foster for 20 days. This year, which marks the seventh year of collecting data in this area, the team will be using new equipment and technology to examine areas of the sea floor off the southern coasts of St. Thomas, St. John and eastern portions of Puerto Rico.

Listening to the Big Picture

NOAA researchers are using an array of tools to collect data that will contribute to a more complete understanding of the coral reef ecosystems and fish habitats around the U.S. Caribbean. One tool being deployed is a new, state-of-the-art multibeam echosounder.

Researchers preparing multibeam echosounder for launch.

Researchers closely inspect the remotely operated vehicle after it is retrieved.

High resolution (Credit: NOAA)

Similar to an ultrasound, the echosounder sends out a swath of 512 beams of sound, which bounce off the seafloor and other objects. These systems measure and record the time for the acoustic signal to travel from the transmitter (transducer) to the seafloor (or object) and back again to the receiver. By analyzing the intensity of the echoes (or return signals), sophisticated computer software will then compose pictures of the physical features of a particular area. From these images, researchers will identify key gathering and spawning sites for ecologically and economically important marine species. 

Exploring Virgin Territory by Remote Control

Researchers also are using a remotely operated vehicle, or ROV, to collect underwater video and still photos of the research sites.

Bryan Costa (NOAA) views live footage collected by the ROV and notes the biological cover on the seafloor.

NOAA researcher Bryan Costa views live footage collected by the ROV and notes the biological cover on the seafloor.

High resolution (Credit: NOAA)

“Using the ROV is an important step because the images from it confirm data being collected through other sources,” explains Bryan Costa, a NOAA geospatial scientist aboard the Nancy Foster. “From the ROV’s video and still images, we can tell what an underwater structure is and what may be growing on top of it,” explains Bryan Costa, a NOAA geospatial scientist aboard the Nancy Foster.

A number of products will be generated from the research conducted during this mapping expedition, including underwater video and photographs; fish distribution and spawning aggregation data; seafloor landscape imagery; and habitat maps describing the geographic location, physical structure, biological cover and live coral cover on the seafloor.

The new data also will be incorporated into updated nautical charts for safer navigation.

Map of study area.

Map of study area.

High resolution (Credit: NOAA)

“Much of this area has not been studied or mapped,” said Tim Battista, oceanographer for NOAA’s Center for Coastal Monitoring and Assessment and principle investigator for the expedition. “The data we collect will paint a clear picture of the U.S. Virgin Island’s underwater habitats and the marine life they support, which is critical to the resource management decision making process.”

Follow the scientists and research activities by reading the daily mission log online. NOAA logo.

Web Resources

Additional information about this project, as well as data collected, are available at the Seafloor Characterization of the U.S. Caribbean Web page.

NOAA Coral Reef Conservation Program

Natioanl Ocean Service's Making Waves Episode 21: 2009 Caribbean Research Cruise [Podcast]

National Ocean Service's Diving Deeper: Value of Coral Reefs [Podcast]

NOAA Ship Tracker