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OUR TRIP TO THE BANK Mission Dispatch 7 - April 10, 2005 | Mark Schrope - @SEA Correspondent Dog and Damas Rocks, Cay Sal Bank 
We began the day with sub and scuba dives at a new section of Cay Sal called the Dog Rocks,
about 35 east of Elbow. Unlike Elbow, with its faint traces of past human occupancy, these
islets are tiny and even more desolate looking above the surface--just a few small pieces
of rock in the middle of the sea. The underwater landscape, though, is still lush. According
to the chart, to get here we passed by the Muertos (Death) Cays, then came around an area
with unexploded bombs, but made it unscathed.
For the afternoon, we moved southeast one more set of islets around to the Damas Rocks and took two small boats in to explore around the islands. The region is known for its blue holes, which are depressions sometimes hundreds of feet deep having steep rock walls covered with life. Sadly, most descriptions John Reed found of the holes did not include GPS coordinates. A couple of scientific papers from the 1980s did include latitude and longitude information, but these were from the days before precise GPS was available, so they can be as much as half a mile off and proved to be no help. We spent over an hour straining to spot a telltale dark blue spot but to no avail. We did find quite a few dark blue spots created by the light trickery of the scattered clouds above, but that didn't do much to help our quest. With time running low, we gave up the search and dove a beautiful reef about 50 feet deep. Later, we snorkeled around a couple of the islands, finding large fields of yellow and purple sea fans. At the base of the islands were small undercuts and caves cut into the sharp limestone rock, and just a few feet out from one island lay the wreck of a small boat. With its metal ribs, the shape of the hull was still visible, and there were bits and pieces of metal scattered all around. ANOTHER NEW SPECIES 
Both Johnson-Sea-Link (JSL) submersible dives were more productive than the past few have been. Each time the scientists returned to the ship with word of extensive rock formations, and some of the largest loads of samples we've had this trip. During the second dive, Shirley Pomponi and Don Liberatore collected a sponge that on the bottom looked to Shirley like a species previously collected, but closer examination at the surface revealed that it was something different. The sample turns out to be of a genus first discovered in a cave in the Mediterranean, but is almost certainly a new species. Even species that have been collected before can prove interesting, because a given sponge's chemistry can vary greatly from one area to another, but it's always exciting to have something brand new to probe. Each time the sub returns, the deck is crowded with team members lining up to rush sample buckets from the front of the sub into the lab, where they are processed for a variety of analyses. Pieces of each sample are cut to prepare extracts for biomedical assays, to save in Harbor Branch's permanent collection of over 30,000 samples from past expeditions, and to culture microorganisms, specifically fungus and bacteria, they harbor. The team has been studying microorganisms growing in the sponges and other invertebrates they collect for many years, but the main focus has been on aerobic microorganisms, which thrive on oxygen. On this expedition, in addition to doing the aerobic work, the team is also doing preliminary experiments with a much less-studied group of microorganisms--the anaerobes. These delicate microorganisms not only don't rely on oxygen, they can be killed by it, and so culturing them requires quick processing. GROUND UP BRAINS AND HEARTS KEEP OUR MICROORGANISMS HAPPY Postdoctoral fellow Wolfram Bruck begins the process by mixing sediment, a chopped up sponge, or other sample, in seawater. Next he takes a small bit of that seawater, which then includes a mix of all the microorganisms found in the sample, and spreads a few drops out on culturing plates filled with commercially available growth media, or agar. For this trip he's using two kinds, a standard marine agar, and something called brain-heart infusion agar, which is made of - you may have already surmised - ground up cow brains and hearts. These decidedly un-oceanic elements are often used in culture work because they are rich in nutrients and so promote growth. "It just makes them happy, basically," says Wolf. And we do indeed want our microorganisms happy. 
Once Wolf makes the plates, he places them in sealed containers with a pouch of scrubbing material that reacts with oxygen to take out 99% of it within about 30 minutes so the anaerobes can feast on the agar and reproduce. The plates stay in the chamber for a few days until microorganism colonies begin to appear as spots of growth that can look something like what you find growing on cheese or bread past their prime. Next, Wolf move the plates to a cold room, which keeps them alive, but does not promote further growth. To maintain the anaerobic atmosphere, the plates at this point are stored in bags pumped full of nitrogen every day or so. Normally such would be done in a laboratory with elaborate anaerobic chambers, but research on a ship almost always involves improvisation. Back at Harbor Branch, Wolf and others will perform additional steps to purify the microorganism cultures started out here to ensure isolation of a single species. He'll then use a technique called Polymerase Chain Reaction, which is the same one investigators use to analyze DNA at crime scenes, to determine the genetic sequence of a tiny section of each microorganism's DNA. He can compare this sequence to those in published databases---there are large public ones as well as Harbor Branch's own microbial DNA library-- to determine if he has isolated anything interesting. In this case, interesting would be a species not in the database, or a species similar to one already known to produce important biomedical compounds. The next step is to ferment the interesting samples in a flask of growth medium to produce a large enough volume of cells to work with. Finally, compounds produced by the microorganism will be tested for pharmaceutical potential. DIVE OF THE CENTURY We've done all we have time to do at Cay Sal, so tomorrow we'll start making our way back toward Freeport. Along the way we'll make a couple of additional stops for exploration. John Reed is particularly excited about a submersible dive planned for the morning to a deep-water pinnacle in about 2,000 feet of water that is marked on the charts but, to our knowledge, has never been visited. The nearest island is Orange Cay, about halfway to Freeport. "It's going to be the dive of the century," says John, "It's going to be too cool." So check back in. 
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