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MISSION DISPATCH 3 August 22, 2005 | Brian Cousin - @SEA Correspondent Two objectives of this mornings JOHNSON-SEA-LINK I (JSL) dive are to deploy Dr. Tammy Frank's traps, and retrieve Dr. Edie Widder's Eye-in-the-Sea (EITS) camera system. Early this morning Tammy and her postdoctoral fellow Jon Cohen were in the wet lab blending what looked like a lumpy cake mix. The pungent odor of fish confirmed this was not for the crew's consumption, but rather to lure crustaceans into the traps with the promise of a tasty meal. 
Observers on yesterday's dives reported an abundance of animals at this location and the team is anxious to see what might have been revealed to the Eye-in-the-Sea in the absence of the JSL with its inherent symphony of thrusters and hydraulics, and accompanying display of lights. Dr. Sonke Johnsen is in the sphere with pilot Hugo Morero. Sonke's graduate student, Dan Speiser is making his first-ever submersible dive in the aft compartment with technician Frank Lomabardo. Sonke's objective is to capture and videotape animals at the bottom and then view only the blue light channel (at around 480 nm) to see if what appears as relatively even coloration under white light appears as effective camouflage in the blue range. All goes well - traps are deployed, the EITS is recovered and Sonke has videotape of animals for his work, although the collection baskets remain empty of live samples. It will take several hours to process and review the digital recordings from the EITS, but Dr. Widder's research group has already determined that one of the new improvements to the system - a hydrophone - shows promise but requires more amplification. Graduate student Erika Raymond eventually reports that of the images processed so far, a sequence of a large cusk eel spanning the screen is the most impressive. A sequence showing the approach of the submersible illustrates how its lights and sounds cause many animals leave the scene. While the scuba divers are out on the second blue water dive of the mission, the decision is made to remain at this location for another submersible dive tomorrow morning, slightly delaying our departure for DeSoto Canyon to the northwest. The Eye-in-the-Sea camera system is redeployed on this afternoon's dive, to be retrieved tomorrow. Tammy's traps set this morning will be recovered and replaced with freshly baited ones to stay on the bottom overnight. Tammy is glad to be staying a little longer at this site because the density of animals here bodes well for her capturing those she needs for her studies. Dr. Mike Matz from the Whitney lab occupies the observer's seat in the sphere to continue experiments in fluorescence started during last year's Deep Scope cruise. Two of the JSL's HMI lights are fitted with blue filters. The JSL's human observers don yellow goggles that block reflected blue light and transmit fluorescence. The submersible's video camera is outfitted with a yellow filter that can be swung over or away from the lens by the pilot inside the sphere. This will allow them to make white light and filtered light observations of fluorescent sources. A number of animals emit fluorescence, which involves absorbing light of one color or wavelength, and reemitting it as another color or wavelength. Last year a number of marine species were found to fluoresce, including a species of shark. Surprisingly, the methane hydrates escaping through the sea floor and rising up into the water column were found to be brilliantly fluorescent. 
It is unknown what purpose fluorescence serves in the deep ocean, or why
some fish that live in the dark depths are capable of emitting complex
patterns of fluorescence. One theory suggests these animals may also live
at shallower depths where they can absorb more light. Another intriguing
possibility is that deep dwellers may be able to absorb bioluminescent
light produced by other organisms to reemit as a fluorescent signal. Or
perhaps, Mike notes, we underestimate how much light there is and the
animals' ability to utilize it it.
The JSL returns to the surface under a setting sun. The science team offloads samples of fluorescent organisms including a brightly fluorescent zooanthid, and a fish with fluorescent "eyebrows". Not all of Tammy's traps came back empty, exactly, but the contents were hardly of scientific value to a visual ecologist. A hagfish had clearly attempted to enter the trap, the trap, leaving a coating of slime all over the trap. Video recorded on this dive showed a gang of large Chacion crabs (too large to enter the traps themselves) guarding the traps once again, and includes a sequence of the crabs fighting off a huge disgusting hagfish. Tammy has been working on a galatheid crab from yesterday's dive all day, and hopefully the traps left on this afternoon's dive will render something as useful. Stay tuned! SIDE BAR Dan Speiser, who made his first submersible dive this morning, reports. As a member of Operation Deep Scope 2005, I had my first opportunity this morning to take a ride to the ocean floor in the JOHNSON-SEA-LINK submersible. I took my position in the aft compartment and, although it was by no means spacious, I found that I could wedge myself into quite a nice position where I could both keep an eye out the starboard portal and watch the video monitor displaying what was visible from the front of the vehicle. Once we'd reached a few hundred feet below the surface, the cabin cooled off and, with the CO2 scrubber humming away behind me, it became quite a relaxing ride to the ocean bottom. We dove at a rate of a little over a foot a second and the light outside my portal grew bluer and bluer. The pelagic zone was thick with animals. Jellyfish pulsed by and cydippid ctenophores trailed their long tentacles. An occasional fish flashed irridescent in the fading light. By one thousand feet little was visible. 
As we approached the bottom, the lights were turned on outside my
window and I got my first look at the deep sea benthos. Life at 1,800 feet was
denser and more varied than I had expected. Among the more fascinating
invertebrates were spiraling, orange soft corals that rose like sprung
bed-springs from the soft, muddy seafloor. Pale, high-domed sea urchins,
the largest I had ever seen, were also common. The flat sand of the
ocean bottom was broken by rocky outcrops that provided a home for stands
of white corals and a variety of long-clawed crustaceans. Fish were
plentiful as well. Hatchetfish, small and silvered, swam by and squat,
wide-eyed fish, mottled red, rested on their pectoral fins on the bottom.
A swordfish, with its distinctive silhouette, showed itself several
times outside my portal.
Once we were at the seafloor, our work began. The submersible was responsible for deploying several traps at a beacon that had been placed on a previous dive and for collecting the Eye in the Sea imaging device. My graduate advisor, Sonke Johnsen, was aboard to investigate the cryptic coloration of benthic animals (I was along to take notes). We completed our tasks without too much difficulty and began our ascent. The submersible lights were shut off on the way up and we were privileged to see an amazing display of bioluminescence. Some animals glowed dimly as they floated past, others flashed brightly on and off. The light outside grew brighter and we were soon at the surface. The crane from our ship, the R/V Seward Johnson , lifted us out of the water and brought us back to the deck, safely concluding our mission. 
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