Clams as far as they can see

Nancy Barr

When the ROV Doc Ricketts arrived at an extensive clam bed deep in Monterey Canyon this morning, it was soon evident that things had not changed drastically since the last time the site was mapped by David Caress and his team. That answered the first question of the day: Did the large turbidity current that moved a massive amount of sediment from high up Monterey Canyon in January 2016 travel this far? Obviously not. This is an important piece of information for Scientist Charlie Paull and his colleagues who are studying the movement of sediment in the deep sea.

But Paull is looking not only at major changes in the shape of the seafloor, but also for small changes in texture that can indicate the movement of sediment. Today’s low-altitude survey conducted with the lidar, multibeam sonar, and stereo camera will provide the close-up look to determine if there have been those fine-scale changes. About half of the 100-meter-square survey area was covered today before high winds required bringing the ROV back up to the ship a little early. Tomorrow the team will continue the survey of this clam bed at 2,850 meters depth. The results of these surveys will be compared with maps of this same site from six previous surveys conducted from 2012 to 2014 to learn more about where and how the seafloor is changing.