Scientists discover deepwater corals off US Coast

NOAA scientists have discovered areas of deep-sea corals in the NOAA Olympic Coast National Marine Sanctuary off the Washington state’s Olympic Peninsula during a recent 12-day scientific research mission on board the NOAA ship McArthur II.

Results from the surveys were dramatic. At least six species of soft coral and one species of stony coral were observed. In some areas scientists encountered fields of erect soft corals known as “gorgonians” with individual colonies as high as three feet and in other areas isolated patches of coral colonies associated with scattered boulders.

Corals observed included giant cup corals, branching soft corals such as “bubblegum coral” and the stony reef-building coral Lophelia, discovered during the earlier pilot cruise in 2004.

“We know that deepwater corals are an important part of the ocean ecosystem, but we know very little about them,” said Timothy R. Keeney, deputy assistant secretary for oceans and atmosphere, and co-chair of the United States Coral Reef Task Force.

“Further study of this area shows promise in expanding our understanding of the ecological role of deep coral habitats, and perhaps even providing insights into the future impacts of climate change and ocean acidification on such important ecosystems.”

During the mission, scientists used a remotely operated vehicle, or ROV, in depths from 300 feet to 2,000 feet to photograph and videotape the coral and sponge assemblages while also collecting specimens with the ROV’s manipulator arms.

This cruise followed up an initial pilot survey in June 2004 when NOAA scientists found small samples of a stony coral, Lophelia pertusa, the most important reef-building deepwater coral in the Atlantic Ocean but rarely recorded off the Pacific Northwest coast or elsewhere in the North Pacific.

“We planned this research mission in the expectation that there would be more of these coral communities based on the limited information gathered in 2004 and from scientific literature,” said NOAA investigator Ed Bowlby, who serves as the NOAA Olympic Coast National Marine Sanctuary research coordinator.

“What we found, within the headlight of our ROV, confirmed that these coral communities are a significant portion of the ecosystem in the sanctuary. What lies outside of that headlight is intriguing and makes us eager to return.”

Researchers observed coral species supporting thriving populations of invertebrates as diverse as tubeworms, shrimp, brittle stars, sea slugs, crab, colonial and solitary sea anemones and feather stars.

Some of the coral assemblages appeared to form aggregation sites for rockfish of several species and pregnant females of at least three species of rockfish were observed nestled among the coral and sponge structure. On several occasions, researchers also saw egg cases of sharks attached to the coral colonies.

The researchers surveyed more than 15 sites, and coral communities were found on portions of all but one of the sites.

Source: NOAA

Images: NOAA