Dive and Discover : Expedition 13 : Gulf of Mexico : Day 10

Today’s dive was all about getting a better picture of the ocean bottom. Alvin pilot Dave Walter took Chuck Fisher and Mike de Gruy down to the Gulf of Mexico seafloor to reposition the time-lapse camera that we had deployed, recovered, and redeployed earlier in the cruise and to take more photographs of corals in the surrounding area. All of those images will give us more data to better understand the possible impacts of the oil spill on the Gulf.

The camera is positioned in 1,373 meters of water and programmed to take one photo every hour for the next two months of a Paramuricea coral colony. The camera only needed to be moved four feet or so forward, but the increase in coverage and image quality was thought to be great enough that Chuck decided to push for the extra day and extra dive, and Alvin went down once more to the place we visited three times on this trip.

Chuck picked this particular coral colony to monitor because it shows a range of exposure to what looks like the same brown substance that is clinging to—and possibly killing—many corals in this part of the Gulf. Some parts of the Paramuricea appear healthy, others are sick, and some parts are obviously dead. If it continues to die or it begins to recover, we will see it happen once the camera is recovered in February.

Precision and repetition are important parts of scientific research, but away from the controlled environment of the lab, the real world can make a mess out of even the most carefully planned experiment. So any opportunity you get, you try to control the variables that introduce uncertainty into your results. That was the real goal today, to reduce the uncertainty in the scientists’ eventual ability to explain what is happening in the Gulf.

In addition to repositioning the camera and taking more images of corals, the team in Alvin also took six more sediment cores, collected a coral sample, and filtered brown material off more corals for analysis. All of this will go toward creating that fuller, more complete understanding that Chuck and many others are after.

Of course, today was also about the final Alvin dive before the sub begins a major overhaul and upgrade that will include a new, larger personnel sphere. The event drew the attention of world-renowned marine biologist Sylvia Earle, who rode all night in a 54-foot fishing boat to come aboard Atlantis and watch Alvin make its dive. Despite the hoopla, it was still a typical last day at sea, as people began to pack their computers, their samples, and, in the case of the Sentry team, their vehicle. Even the Alvin Group, which normally makes its home on Atlantis, was busy preparing to leave the ship later in the week by collecting and packing years’ worth of spare parts, records, and the countless odds and ends it takes to run the most successful human-occupied research submersible program in the world.

So that’s about it. We’re steaming for home at 10 knots in calm seas under a clear sky. A few people are out on deck looking for shooting stars. One or two of the scientists who still have samples to process are hard at work finishing up so they can turn in. Word is we will have to linger at the sea buoy outside of Gulfport before we can pick up our harbor pilot because there is a banana boat due into port ahead of us. Many thanks to the captain and crew of Atlantis and the Alvin team for keeping us safe and helping us do our jobs by doing theirs so well.

First-time Divers: Andrea Quattrini and Pen-Yuan Hsing made their first dives in Alvin during this cruise. Dive and Discover reporter Ken Kostel sat down with them to find out about their experiences. Read the interview »

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