April 27, 2003 -- Dive Day 1

Slideshow

Gretchen Früh-Green

		April-May Sun Mon Tue Wed Thu Fri Sat 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Today's Question Q. How much does Alvin weigh? How does it float? A. Alvin weighs about 35,000 lbs. While it seems too heavy to float, there are large blocks of a special, dense foam called "syntactic foam" that makes Alvin buoyant in the water. When Alvin is deployed, it carries an extra 960 lbs of weight to make it sink to the seafloor. Air tanks balance that weight until the pilot is ready to take it to the bottom, then the air tanks are flooded with seawater. When the sub reaches the bottom, half of the weight is released so that it can move freely. When ready to end the dive, the pilot releases the rest of the weight and Alvin comes back to the surface.

The day we have all been waiting for has finally arrived – we are ready to start our science program. We are on site, the transponders are in place and the first dive day has begun.

Almost everyone was outside to watch Alvin being launched this morning at about 8:00. For those who have never seen it live, it is a fascinating thing to watch. The Alvin is rolled out of its hanger, the Avon (a small rubber motor boat) is waiting to be put overboard and the “Swimmers”, Gavin and Raul, are in their wetsuits ready for a brisk morning swim. Their job is to unhook the sub after it is lowered into the water. Debbie

Debbie Kelley and Tim Shank prepare to enter Alvin for the first dive of the cruise.

Kelley and Tim Shank are the first to dive this cruise, and Bruce Strickrott is their pilot. It will be an exploratory dive aimed at getting a range of fluid, rock and biological samples.

During the day those of us left on the ship follow their progress either through updates given by the bridge or on lighted displays in the labs. After about 15:30, we start to anxiously await the horn that signals that Alvin will be surfacing. The horn finally sounds, and the Avon is once again lowered into water. Phil and Gavin are ready as Swimmers this time and Jerry drives the boat.

Ken Rand of the R/V Atlantis heads out to pick up the Alvin divers.

The Alvin surfaces at a distance in front of the ship and the Avon approaches them. There is a telephone just above the hatch on the Alvin and one of the swimmers climbs aboard and lets the scientists know that the ship is coming. It seems to take forever for the ship to slowly approach the sub, but then we get there and it is towed in and lifted up onto deck with the A-frame. Everyone is excited to know how the dive went and see the samples that were collected.

The A-frame on Atlantis hoists Alvin and its divers overboard for deployment.

Debbie and Tim were pleased with the dive. They got the samples they wanted. Eric Olson and Dave Butterfield take care of the water samples, Kate Buckman and Tim take care of their little critters, and Jeff, Debbie and I sort out the vent samples. In the labs everyone is suddenly very busy. The first measurements are made on the fluids; the vent structures are sampled for microbiological studies and organic geochemical measurements.

Mitch Elend photographs all the samples; then each is measured, weighed and described. Before we know it, it is time for dinner and a quick science meeting. Tim and Debbie review how the dive went and show us some pictures of the structures. They are absolutely fascinating and I am sure I’m not the only one that can’t wait to see them “live”!

Tonight at about 20:45 we launched ABE, the Autonomous Benthic Explorer, for a test run. If all goes well it will stay in the water for a few hours and then will be followed by another CTD (conductivity- temperature-depth) run. This is just the start. For the next few weeks, we will have round-the-rock operations, collecting a tremendous amount of data – and hopefully leading us nearer to understanding the intriguing hydrothermal system that has built up Lost City.