Our first dive
July 13, 2012
I am one of MBARI’s summer interns and I got the opportunity to join the Midwater Ecology cruise on board the R/V Western Flyer. This is my first cruise and I am in charge of reporting the research team’s activities.
We left the dock at 8:00 a.m. and headed to the Midwater Respirometry System (MRS) mooring site in Monterey Canyon. The remotely operated vehicle (ROV) Doc Ricketts is launched through the moon pool, a door that opens up in the center of the ship’s twin hulls. The science team and the ROV pilots watch the launch on monitors in the ROV control room.
In the control room, there are two ROV pilots, one flying the ROV and the other in charge of managing the tether and controlling the vehicle’s manipulator arms. Next to the pilot, there is a chief scientist’s chair, where a member of the science team controls the main high-definition video camera and looks for our target animals. There are five pilots on board and each pilot spends an hour at the co-pilot seat then an hour as pilot, and then gets a break from the control room. Dives generally last 12 hours each day.
Our first mission was to deploy the MRS at 320 meters (1,050 feet) depth. The MRS is composed of eight chambers where oxygen consumption is measured; other gases, such as carbon dioxide, can also be manipulated and the results recorded. We collected one Sergestes similis (a shrimp living in the upper water column) in each of six chambers. Two chambers hold only water to provide controls for the experiment. Doing this type of experiment in the water column instead of in the lab assures us that the measured respiration rates are the same as these animals normally respire. Once we filled all of the chambers, the MRS is “hung” on a mooring and it will stay there for 48 hours. In two days, we will return to recover the MRS and download the data.
We then dove down to 800 meters (2,600 feet) looking for the vampire squid. Unfortunately, we didn’t find one today, but perhaps another day! We did, however, see many other types of squid, including this Cockeyed squid (Histioteuthis heteropsis).
To collect these animals we have two types of samplers available. The suction sampler sucks water to bring the animal into a bucket. The detritus sampler is basically a bucket opened on both ends. The pilots fly the vehicle so the animal is within the bucket and then they close the top and bottom to keep the animal and its surrounding water within the sampler. This allows us to collect the animals with relatively little disturbance.
Tonight we will deploy a camera system over the side of the ship to observe the behavior of deep-sea animals, especially squid. We’ll let you know how that goes tomorrow!