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MISSION DISPATCH 8 August 29, 2005 | Brian Cousin - @SEA Correspondent We are in port at Galveston Texas, rafted up to the Texas A&M Research Vessel Gyre. While we contemplate our own problems with the ship's malfunctioning winch, we are mindful of the problems facing the millions of people in the path of hurricane Katrina. Many of the crew are following the storm on the ship's satellite television. Two members of the NOAA Ocean Exploration team on board have homes and families in the New Orleans area. 
Yesterday, the replacement brake cylinder for the submersible's winch
arrived and was installed by the R/V
Seward Johnson's
engineers and members of
the sub crew. Unfortunately, the new cylinder did not solve the problem,
and attention turned to sequencing valves in the system that control
engagement and release of the brake. Parts have been ordered and should
arrive today. Before they can be installed, they will have to be taken to
a facility in Galveston where they can be set up and tuned to the correct
settings.
We may not leave port before Wednesday due to conditions in the Gulf of Mexico following hurricane Katrina. To recover Dr. Tammy Frank's benthic traps and Dr. Edie Widder's Eye-in-the-Sea (EITS) camera, we have to return to Vioska Knoll, about 68 miles south of Mobile, Alabama, where Katrina passed at maximum strength. We are quite certain the scientific packages, located on the bottom at a depth of about 1,800 feet, will be unharmed. We are not certain, though, what we may find floating around in the gulf. While we are unaware of any confirmed damage reports, many large oil platforms in the area were subjected to Category 5 hurricane winds and pounding waves. 
In the dry lab, Dr. Tammy Frank is experimenting with another of the galatheid crabs she collected five days ago using the JOHNSON-SEA-LINK I (JSL) submersible. She was fortunate to capture three perfect specimens and so her work with the electrophysiological prep continues without pause, at least for now. Remarkably the first crab, a species of Gastroptychus, has very high UV sensitivity as well as high sensitivity in the blue wavelengths. The other species, Eumunida picta, appears to have just blue sensitivity, which is expected in a deep-sea species, as blue light penetrates the deepest in clear ocean water. The discovery of UV sensitivity in a deep-sea benthic crab is completely unexpected, and for now, the reason behind this adaptation remains a mystery. Dr. John Cohen is at his prep, with a sargassum shrimp as a subject. Graphs on his computer indicate a quick response to light stimuli, as might be expected of an animal that lives in the brightly lit surface waters. "It sure would be nice to get back to Vioska Knoll for more Pontella", he says, referring to the copepod Pontella securifer with the triplet lens eye that he has also been studying. 
Dr. Sonke Johnsen is "normalizing" images of animals taken by the submersible that he can then examine to determine how cryptic, or camouflaged, they appear in the red, green or blue color channels. First he adjusts for certain aberrations in the image that could be caused by particulates in the water, closeness to the subject or color balance settings in the camera. Sonke explains, "It makes black things black and white things white. Then I split the image into red, green and blue color channels and look at each channel. Animals should be more cryptic, or better hidden, in the blue channel, meaning they blend in with the color at depth. There's no reason as far as we know for crypsis in the red or the green." Sonke has found that some animals recorded in the darker depths at Vioska Knoll don't hide so well in the blue channel, perhaps because there are other challenges to hiding in the blue, like bioluminescence. "The great thing about looking at images this way is that there aren't any special filters required in front of the sub's camera or lights. You can look at any previously shot images from the sub and split the color channels." 
Dr. Justin Marshall is making notes on chapter seven of a text that he is reviewing for the publisher. "The Senses of Fish Adaptations for the Reception of Natural Stimuli" edited by Gerhard Vonder Emde, Joachim Mogdans and B G Kapoor is the latest on the subject. As a scientist engaged in such studies himself, Justin says it's nice to be reading this newest release as stimulus for thought. Dr. Mike Matz is reviewing proofs for a paper as well as a couple of grant proposals. While everyone is keeping busy, they all would prefer to be diving in the submersible in the Gulf of Mexico rather than port-bound in Galveston. Collections and more collections of samples and data should fill our days at sea. Hopefully, the gulf will lie down quickly after hurricane Katrina's passing and the sub will be ready to continue diving following repairs to the winch that are underway. 
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