DISCOVRE 2008

Cruise Log: 10/23/2008

Leg 2 Summary: Mapping Summary

Steve W. Ross, Chief Scientist

We are now only a few hours from Key West, Fl, from which the science crew will fly home tomorrow. The type of work we just completed can be very monotonous and has even been compared to mowing the grass. For multibeam mapping, the ship steams back and forth over predetermined tracks, covering the bottom with multibeam sonar, and stopping periodically to take CTD casts. Despite the apparent dullness of this work, it is vitally important to our overall objectives of understanding and better managing deep-sea ecosystems. The science crew and survey technicians still stand 24 hour watches and must view the mapping data to note unusual features that may need more attention, to check data quality, and to note whether the ship's track needs adjustment based on the collected data.

Over the last few days, we have mapped an area of the continental slope covering about 47 x 4.5 km or about 222 sq km. These are the first maps of such detail for this area. In fact, most of the US outer continental shelf and waters beyond are very poorly known. The most prominent feature we saw is a long scarp about 30-50 m tall running north-south nearly the whole length of our survey area. Seaward (westward) of this scarp are numerous (perhaps thousands) of scattered mounds and ridges about 5-20 m tall. Many of these may be dead or living deep-sea coral features, but proving that will have to wait until we can visit them next year. This area is quite different from the Gulf of Mexico deep reef habitats we examined earlier this month and those we have worked on off the southeastern US. Comparing these ecosystems will provide insight about how these systems form, are maintained, and their status (growing, declining, young, old).

Now comes the months of data reduction which we have already started in numerous labs: Leetown, WV; Washington, DC; Texel, the Netherlands; Oban, Scotland; Wilmington, NC; Gainesville, FL; St. Petersburg, FL; Chapel Hill, NC. Potentially other colleagues will also join us as we unravel the gigabytes of data and thousands of specimens collected. We hope to continue to provide updates on this work over the next 3-4 years. Who knows what we will DISCOVER.