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MISSION DISPATCH 5 August 24, 2005 | Brian Cousin - @SEA Correspondent After a 20-hour steam to Desoto Canyon, first mate Mike Schoeller began running transects over the site. Mike, chief scientist Dr. Tammy Frank and sub ops coordinator Craig Caddiagan looked for any ridges, bumps or mounds on the bottom to be reflected on the R/V Seward Johnson's fathometer display. Contours on the display translate to the likelihood of hard bottom - the type of substrate that will support populations of animals the researchers need for their work. Desoto Canyon has been little explored. After a 40-minute transect reveals a gradual depth change of only 100', Mike declares the canyon to be a ditch. It is not at all like the steep-walled chasms the researchers have explored in the Gulf of Maine. 
Dr. Tammy Frank and Dr. Edie Widder wisely opt to allocate this morning's dive in the JOHNSON-SEA-LINK I (JSL) to training, and pilot-in-training Frank Lombardo takes the controls. Seasoned pilot Tim Askew, Jr. takes the seat in the sphere normally reserved for the principal investigator. One in every ten dives in the sub is allocated to training to help cultivate skilled JSL pilots and technicians. Frank and Tim take the JSL to 2100 feet. They have not taken any of Tammy's benthic traps or the Eye-in-the-Sea (EITS) to leave on the bottom, but they have taken one of the Bio-Boxes in case they can capture something using the suction device while they're down there. Frank's voice comes over the radio on the bridge to deliver the bottom report. Depth, current speed and direction, temperature, visibility and a description of the bottom are recorded by Jim Sullivan at the Comm-Track. Frank confirms that the bottom is flat white mud. This is Frank's seventh dive as pilot-in-training in the JSL. After almost seven years at Harbor Branch, two of those spent as a certified aft observation chamber technician, the opportunity came to start training as a pilot. "I know the systems and I've passed the written exams. Now it's all about getting time at the stick. It's kind of like riding a bicycle, only after you ride it once, you don't get to ride it again for a while. It just takes practice to operate the sub in all kinds of sea conditions and use the collection devices so you can do a good job when there's a scientist in the seat next to you". 
After the dive, the decision is made to depart immediately for Vioska Knoll, about 55 miles west of here. Vioska is known to support substantial populations of animals of interest to the research team. During last year's Deep Scope cruise, the sub dove on magical gardens thick with anemones, grouper and other fish. They'll dive on sites a little deeper than last year, below the realm of visible down welling light. As the ship makes its way westward, we begin to see some of the oil rigs that dot the gulf and the ships that tend them, bringing fresh supplies and workers to staff these enormous platforms. Second mate Stewart Bell advises everyone via intercom that there are whales off the starboard bow and most of the science team heads to the 02 deck with cameras to take a look and hopefully get a shot. A plume of exhaled vapor is seen once or twice in the distance and then the flick of a tail as the whale initiates a dive that could last twenty minutes or more. As members of the NOAA Ocean Exploration team reviewed video from yesterday's dives, they come across footage of the 6-gill shark swimming near Edie's Eye-in-the-Sea camera. At one point, the subs low-power laser passes over one of its eyes, producing a brilliant flash. Six-gill sharks have a tapetum in each eye, a reflective layer that increases the sensitivity of the photoreceptors responsible for the animals' vision. Many other animals have tapeta to help them see in the darkness - cats, and the way their eyes appear to glow in the dark are a familiar example. 
The sub is down on the second dive of the day to deploy the Eye-in-the-Sea and Tammy's benthic traps. She and post-doc Jon Cohen have used the transit time to bring the traps up to 'Plan C' specs. It was a good time for a redesign, since two of the traps had to be cut apart anyway, having been slimed beyond redemption by the disgusting hagfish. One end has been closed to prevent the possibility of animals falling out when the trap is retrieved, the interior material has been changed from monofilament to plastic mesh, and the center of balance has been changed to facilitate easier deployment and recovery to the sub. These are substantial changes in response to the real life conditions found at the bottom of the sea. Apart from those changes, Tammy has another strategy she hopes will keep the large crabs and disgusting hagfish away from her traps. As a diversionary tactic she'll place a bait bag a short distance away from the traps hoping that the non-target animals will flock to the easy pickings. The smaller target animals might then make it into the traps. Tammy will also try to capture samples with the sub's modified suction tube and bring them back in the light tight Bio-Boxes (the 'Plan B' spec). We hold our breath as the sub returns from the depths and is lowered into its cradle back on the deck. It becomes apparent by the way the researchers and sub crew are handling the Bio-Boxes there is something inside. In fact, Tammy has brought back four crabs in perfect condition for visual experiments: collected under red light they cannot see, brought to the surface in light-tight insulated Bio-Boxes and whisked into a chilled and darkened environmental room that resembles a walk-in freezer. Those gathered outside can hear muffled voices flush with excitement through the heavy insulated door. 
"Look at those beautiful eyes!", Tammy exclaims referring to her fine collection of galatheid crabs. There is more than one species, so Tammy can do comparative studies, and also verify her findings about the two optical pigments and sensitivity to ultra-violet light she recorded on the single crab she collected previously. The 'Plan B' method of collection, appears to work well. Of 'Plan C', Tammy says a big hake shook the decoy bait bag around and a number of Chaceon crabs appeared to be making tracks for it. Almost unbelievably, there were no disgusting hagfish in sight. We'll see just how well Plan C works when the benthic traps are retrieved tomorrow, but there is cause for optimism. 
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