When University of Delaware marine biologist Mark Warner and his research team finish their first day of diving at Conch Reef in the northern Florida Keys on September 13, they won't be returning to a hotel on the surface.
For the next 10 days, they'll be parking their scuba gear in Aquarius, a kind of high-tech, underwater camper outfitted with many of the comforts of home, from bunk beds, a hot-water shower, and a microwave, to a trash compactor, air conditioning, and even Internet access.
Operated by the National Oceanic and Atmospheric Administration (NOAA) as an underwater research laboratory, Aquarius is 43 feet long, 16-and-a-half-feet wide, and 20 feet tall. Currently, the lab is stationed 63 feet underwater in the Florida Keys National Marine Sanctuary.
Each day of their mission, Warner and his team will dive from the lab to the surrounding reef to learn more about the microscopic plants that live inside the stomach cells of key reef-building corals such as star boulder coral, brain coral, and mustard hill coral.
These algae, through the process of photosynthesis, supply the coral with the food and energy it needs for calcification and growth and thus are critical to the reef's health.
"My previous research has shown that the symbiotic algae living inside the coral may react differently during periods of stress, such as coral bleaching, when seawater gets too warm and photosynthesis in the algae breaks down," Warner says.
Last summer and earlier this year, the researchers studied several species of coral living in shallow water, from 15 to 30 feet deep. During this mission, they will be focusing on the same coral species, but at deeper depths, from 50 to 110 feet underwater.
"What's really interesting is that most of these corals contain different types of algae as you go deeper, yet we know very little about how different these algae are physiologically," he says. "This is an important question since the algae provide lots of food, in the form of photosynthetically produced carbon, that the coral uses for growth and reproduction."
Using hand-held chlorophyll fluorometers and other research tools, the aquanauts will measure photosynthesis in several coral species at different depths, investigate their nitrogen and carbon uptake, and follow how the proteins that are involved in photosynthesis change over the day inside the algae in the corals.
"We'll also be taking advantage of the power supply in Aquarius to heat seawater in small flow chambers where we can follow the effects of thermal stress in corals on the reef," Warner notes.
Some of the mission also will be spent investigating how different species of corals react when exposed to slightly elevated levels of nutrients -- a growing concern worldwide as increasing amounts of nutrient-rich pollutants from land reach the sea.
"It's long been thought that corals can only survive in seawater that contains very low nutrients. However, some researchers are beginning to challenge this notion in some circumstances," Warner says. "The reef where we will be spending most of our time receives several pulses of nutrients from deep-water upwelling. We'll be working to determine how the corals and their algae may utilize these nutrient pulses over a few hours."
Warner's underwater research team will include Jennifer Robison, a master's degree student in marine biology-biochemistry at the UD College of Marine Studies, and graduate students Dan Thornhill and Geoff Chilcoat from the University of Georgia.
As the scientists conduct their work under the sea, Rebecca Thur and Susan Curless will serve as their support team in a boat on the surface. Thur earned her master's degree from the UD College of Marine Studies in 2002 and currently is the coordinator of the Freshwater Submerged Aquatic Vegetation Partnership at the Chesapeake Research Consortium. Curless is a research technician in biogeochemical oceanography at the college.
"We'll be eating freeze-dried camping food while we're in Aquarius," Warner says. "Our surface team will be diving down to visit us mid-way through the mission and delivering us some good junk food like a couple of cheeseburgers. I have a feeling we'll be ready for some food like that."
While Warner has been scuba diving since 1986, this will be his first experience conducting research in an underwater lab.
"Working from Aquarius is truly a one-of-a-kind experience for a marine biologist," he notes. "You essentially let your body become completely saturated with nitrogen during your long stay undersea and then you go through a 17-hour decompression period before returning to the surface."
Once back on the surface, the scientists will be put on a 24-hour medical watch for decompression sickness. If all is well after another 48 hours, they will be approved to fly back home.
"It takes a lot of planning logistically to do research like this, but it's also very exciting," Warner says.
While the scientists go about their work examining the brightly colored corals on the reef, they are likely to have good company in the form of angelfish, parrotfish, butterflyfish, and spiny lobsters, just to name a few.
"We've also been informed that a bull shark has recently been visiting the reef. Earlier this summer, one of the scientists had a closer look at it than she preferred," Warner says, smiling. "We're hoping it won't be around when we're there!"
During the expedition, Warner will be making daily reports on the Aquarius Web site at http://www.uncw.edu/aquarius.
His research is supported by NOAA's National Undersea Research Program.