Despite having to evade hurricane Katrina, a team ofscientists from Harbor Branch and other institutions is returning toport this Sunday with new tales from the deep after completing theirsecond annual Deep Scope expedition. The group has discovered amysterious visual capability in a deep-sea crab; captured new video ofa large, recently discovered squid species; and took clear video of theworld's first known fluorescent shark. The Commerce Department'sNational Oceanic and Atmospheric Administration funded the mission tosites around the Gulf of Mexico.
The expedition, which began Aug.19, is taking place aboard Harbor Branch's Seward Johnson researchvessel and the Johnson-Sea-Link I submersible, capable of diving todepths up to 3,000 feet. The mission's overall purpose is to use avariety of new technologies to gain a better view of deep-sea life, andto understand how that life itself views the deep sea.
The teamhas targeted hardbottom landscapes such as a coral mound about 200miles west of Tampa and the Viosca Knoll, about 140 miles southeast ofNew Orleans. Though the team was able to conduct dives at bothlocations early on, hurricane Katrina forced them to run for Galveston,Tex., where they took shelter for 3 days before heading back out.
Theship's crew took special precautions as they cruised from Texas back tothe Viosca Knoll to avoid hurricane debris. They encountered extensivegarbage, but nothing that threatened the ship. They also saw signs ofdamage on oil rigs and heard reports from other ships that all rigswithin a 50-mile-wide swath beneath the hurricane's path appeared to bethrashed beyond operable condition.
Amidst calm seas, submersibledives resumed today and will continue through Saturday, Sept. 3,offering ample opportunity for additional discoveries.
"Consideringthat a category 5 hurricane just went through this area, I'm surprisedthat we can be out here and diving again so soon," says Chief ScientistTammy Frank, a visual ecologist from Harbor Branch, "it really isastonishing how quickly the seas have laid down."
Frank has beenconducting detailed studies of how the eyes of animals on the deepseafloor work, in collaboration with others aboard. Working withanimals collected in special light-tight devices that avoid damage todelicate deep-sea eyes, Frank has discovered a species of deep-sea crabthat can detect ultra-violet light, despite there being no knownultraviolet light in deep water. UV sensitivity is common in animalsthat live closer to the surface, but has never been discovered in adeep species. The reasons for this seemingly bizarre ability are notclear, but the sensitivity could point to a deep-sea light source aboutwhich researchers are not aware, or to some unknown characteristic ofknown light sources such as bioluminescence--the light chemicallyproduced by countless open ocean organisms.
One key instrumentused on the expedition to help humans see in the deep sea is theprototype Eye-in-the-Sea camera system, which was designed by EdithWidder, former Harbor Branch senior scientist who recently foundedOcean Recon in Ft. Pierce, Fla. This system is deployed on the seafloorusing the submersible and left for 24-hour or longer intervals to filmanimals and activities using very low levels of infrared lightvirtually invisible to deep-sea animals. This allows an exceptionallysensitive intensified camera to capture natural behaviors and footageof animals that have evaded scientists that used other, more disruptivetools such as relatively loud ROVs and submersibles with their brightlights.
Last year, the system captured footage of a six-footsquid believed to be a new species. This year, at a site hundreds ofmiles away, the camera caught footage of what appears to be the samespecies, which would suggest that the squid is not rare, and would alsoillustrate how poorly explored the deep sea remains if such a largeanimal could have gone undiscovered. The squid appears to have beenattracted by a flashing light lure designed to mimic a deep-seajellyfish's bioluminescent display. Much remains unknown about howanimals use bioluminescence, and one of the key goals forEye-in-the-Sea beyond basic observation is to use the bioluminescencelure and other techniques to learn how animals use the light theyproduce.
Based in large part on the success of last year'sexpedition, Widder has been awarded a $500,000 National ScienceFoundation grant to build a more advanced Eye-in-the-Sea incollaboration with Harbor Branch engineers, a project now underway.
Priorto the hurricane, the Deep Scope team was also exploring fluorescencegiven off by deep-sea animals. Fluorescence occurs when an animal orobject absorbs light of one color and then reemits light of, or glows,another color. In the ocean, detecting fluorescence can allowscientists to spot animals that would otherwise be too effectivelycamouflaged to see. Fluorescence is also important because the proteinsthat allow animals to fluoresce are used in genetic research and newfluorescent animals may contain proteins that offer novel benefits insuch work.
Mike Matz, of the University of Florida's WhitneyLaboratory in St. Augustine, and others aboard are using powerfullights mounted on the front of the submersible to illuminate animalswhose fluorescence is then captured on the sub's video camera using afilter that blocks non-fluorescent light reflected back.
Lastyear, using this technique, the group discovered the world's firstfluorescent shark, a previously known species called a chain dogfishwhose fluorescence had never been observed. To their dismay, though,the team was unable to capture the fluorescence clearly on film. Duringthis year's expedition, Matz was ecstatic when he came upon a sharkkind enough to rest on the bottom in front of the sub, allowing him torecord incredible video footage of the animal's intricate fluorescentpattern, not unlike that of the fictional glowing "jaguar" shark in thefilm The Life Aquatic, which it may be worth noting came out monthsafter the team made its discovery.
Daily dispatches from theexpedition team and extensive background material on their work isposted at oceanexplorer.noaa.gov, with additional materials at www.at-sea.org.
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