Missions Header Graphic
2010 Deep Sea Coral Cruise - east coast
Mission info 2007 Nancy Foster Cruise
 

Mission Log: Apr. 14, 2010

Deep coral at last! Or, 'If at first you don't succeed, try, try again'.
By Kevin Stierhoff, John Butler, Scott Mau, and David Murfin
NOAA Southwest Fisheries Science Center's ROV Team

Previous attempts at conducting remotely operated vehicle (ROV) operations in deep coral habitat proved unsuccessful due to strong currents from the Gulf Stream, strong winds, and rough seas that made deploying and piloting the ROV challenging (for the pilots) and dangerous (for the ROV and the deck crew).  After several other successful ROV dives in shallower and calmer waters northwest of the original study area along the Latitude 31-30 Transect, we made one last attempt at getting the ROV to the bottom in deeper waters (>300m) that are known to be habitat for some of the corals (Lophelia sp., for example) we initially set out to find.

A golden crab stands his ground as the ROV approaches.
A golden crab stands his ground as the ROV approaches. Click here or on the image for a larger version.
Upon arriving at the proposed dive site, we found surface currents similar to those that made previous attempts unsuccessful (3-4 knots at the surface).  After conferring with the ship’s officers, we decided a different approach where instead of trying to maintain a fixed location with the ship; we would allow the ship and the ROV to drift freely in the current, an approach aptly described as a “Nantucket Sleigh Ride” by the ship’s commanding officer.  With a lot of hope and a little trepidation, we turned the ship broad to the wind and launched the ROV over the starboard rail.

A tuft coral (Lophelia sp.) surrounded by dead coral rubble.
A tuft coral (Lophelia sp.) surrounded by dead coral rubble. Click here or on the image for a larger version.
It was a long and slow descent toward the seafloor 400m (~1200’) below.  As the ROV reached 300m, we noticed that we could see the end of our tether, which indicated that we may not have enough left to reach the bottom.  At long last, however, we had the bottom in sight and started to see some of the critters that we had come here to see.  Tuft corals (Lophelia sp.), sea fans, and black corals were scattered on small patches of dead coral rubble that dispersed within areas of large sand waves.  We flew along at about 2 knots above the coral mounds, pausing occasionally to snap a quick photo before being forced to move ahead.  Unfortunately, the speed of our drift made it impossible to attempt any sample collections at this site with the ROV.  However, we did collect some good video footage and identified several promising areas where we could return to conduct grab samples later that day.  All in all, it was a very successful expedition!

leaving site indicates a link leaves the site. Please view our Link Disclaimer for more information.
Revised April 14, 2010 by Sanctuaries Web Team | Contact Us | Web Site Owner: National Ocean Service
National Ocean Service | National Oceanic and Atmospheric Administration | Privacy Policy | For Employees | User Survey
http://sanctuaries.noaa.gov/missions/2010coral_east/log_041410.html