Wednesday, November 06, 2002

Key Largo, FL -- Aquanauts participating in the final Aquarius mission of 2002 will combine traditional hands-on research methods with innovative technology to study the condition of coral reefs in the Florida Keys. It is well documented that coral reefs in Florida and throughout the Caribbean are in serious decline. There is increasing concern that the greatest long-term threat facing coral reefs is related to global warming. The problem for corals is that an increase in water temperature, even a degree or two in the summer, can cause a stress response that turns corals pale in color, slows growth, reduces reproduction, and sometimes results in death. In addition to this phenomenon, known as coral bleaching, regional problems related to pollution and overfishing are also well documented. To better understand these various factors, scientists will take up residence on the seafloor in Aquarius – starting Nov. 11 - for 10 days of intensive underwater studies.

Aquarius is an underwater laboratory where scientists live and work on the seafloor for extended periods using a special technique called saturation diving. The 12-foot by 43-foot habitat is located in the Florida Keys National Marine Sanctuary, 60 feet underwater, and 3.5 miles offshore. Owned by the National Oceanic and Atmospheric Administration (NOAA) and operated by the University of North Carolina at Wilmington (UNCW), Aquarius is the world’s only undersea research laboratory dedicated to research and exploration.

As with each Aquarius mission, the November effort involves a six-person crew. The aquanaut team includes: Principal Investigator Mark Patterson, and Ph.D. candidates Janet Nestlerode, Jo Gascoigne and Elizabeth Hinchey, all of whom are from the Virginia Institute of Marine Science (VIMS), College of William & Mary. UNCW habitat technicians Jim Buckley and Byron Croker round out the aquanaut team. Their duties, along with the topside crew led by Aquarius Manager Craig Cooper, are to operate and maintain life support systems for the undersea laboratory. Topside science support will be provided by Lawrence Carpenter and Kristen Delano, VIMS graduate students, Daniel Gouge, VIMS Diving Safety Officer, and Lauren Batte, from NOAA’s research headquarters in Maryland. During their 10-day mission, the scientists will conduct sophisticated experiments using state-of-the-art technology to investigate how local currents (Aquarius operates on the edge of the Gulf Stream), underwater topography (the "roughness" of the reef), and water temperature interact to affect the bleaching response of corals.

Much as a physician evaluates the condition of an athlete running on a treadmill, with tubes and electrodes measuring human physiology, Dr. Patterson and his team will measure dissolved oxygen concentrations in waters that bathe the reef. They will use a unique handheld instrument during their scuba excursions to construct a high resolution map of dissolved oxygen on the reef, including measurements around coral heads, sponges, algae-covered hard bottom, and above sand covered patches. The map will be useful because oxygen dissolved in water is much more variable in concentration than oxygen in our atmosphere, and corals – like any other animal – require oxygen to support metabolism (that is, to stay alive!). However, corals cement themselves to the reef bottom early in life so they can’t move in response to high or low oxygen conditions. Thus, corals depend upon water currents to deliver oxygen essential to their survival. Imagine if you required wind to deliver enough oxygen to breathe, or what it would be like to find oxygen levels changing dramatically as you moved around your house, or at different times of the day. This hidden complexity, and its affects on corals, is a focus of Dr. Patterson’s research program.

Earlier this year, Dr. Patterson and his team conducted topside studies to measure reef oxygen dynamics across the entire reef, not just individual coral heads. The only way to conduct such studies is to use an underwater robot, in this case a Fetch class Autonomous Underwater Vehicle (AUV). Scientists frequently use underwater robots in their studies, but “Fetch” is unusual because it flies through the water based on computer programs that tell it where to go and when to sample. No cables or tethers connect Fetch back to the surface, or Aquarius. Its internal electronic brain and environmental sensors can “fly” patterns across vast stretches of the coral reef, night and day, far longer and deeper than even saturated Aquarius aquanauts can range. Fetch flights can last hours and cover tens of kilometres; the robot has already visited the Aquarius site twice this year, swimming more than 100 nautical miles back and forth over the reef, and uncovered interesting patterns in the distribution of oxygen. The combination of AUV surveys and measurements made during the Aquarius missions will provide the first highly detailed look at how oxygen varies over an entire reef.

Importantly, the motion of the ocean (as defined by currents and waves) may affect how quickly corals respond to various changes in the environment, especially temperature. Also during the mission, the aquanauts will use Aquarius to provide electrical power to heated flow chambers that contain experimental corals. The scientists will initiate and then carefully watch the process of coral bleaching using underwater video cameras and an instrument that measures coral photosynthesis. A question that the scientists will specifically answer is, “do corals bleach more quickly in stronger currents?” This is important because patterns of coral bleaching are often quite patchy on a reef and explanations for why some corals bleach and others don’t remain vague.

During the mission, Aquarius will also engage in two live interactive video links: one with the Shedd Aquarium in Chicago, on Thursday, Nov. 14 at 12 pm EST and the other with the Orlando Science Center on Saturday, Nov. 16 at 1 pm EST. The latter to be hosted in Orlando by a former Aquarius aquanaut, Dr. Ellen Prager. Also, a marine studies class from Coral Shores High School in Key Largo, Florida, will visit Aquarius – the fist time a high school class will dive the underwater laboratory. Throughout each Aquarius mission, expedition journals, photos and live undersea webcam views of the laboratory and surrounding area are available on the Aquarius website, along with detailed program information. Visit the Aquarius website at: http://www.uncwil.edu/nurc/aquarius.