Dispatch from the Deep: Weather Conditions over the Deep Seas

Part of the Deep Sea Vents Curriculum Collection.

Photo of the Deep Submergence Vehicle ALVIN
Deep Submergence Vehicle ALVIN. Photo © University of Washington, American Museum of Natural History, and Pennsylvania State University.

Greetings from the Atlantis! Now that I've got my sea legs and my sea stomach,  I'm enjoying life on board. I'm certainly never lonely; the Atlantis maintains a crew of 22, and there are an additional seven technicians and pilots assigned specifically to the ALVIN. It really does take all those people to keep the ALVIN properly manned and maintained! Along with all the crew of the research vessel, there's a whole scientific team; it includes deep ocean researchers in geology, micro- and marine biology, ecology, and chemistry. Then, of course, there's the five REVEL teachers, including me. Total on board— 54 people, all here to keep the ship going and to study the deep sea vents in one way or another!

I get to learn a lot about what different researchers are studying; every day we have meetings to discuss the research being conducted that day and to prepare for the next research missions. Today we met to talk about the conditions necessary for the launch of the ALVIN. I would've thought that the weather above the sea wouldn't matter for research being conducted 2,300 meters (~1.5 miles) below the sea's surface, but the ALVIN can't be sent down in any and all conditions. A few days ago, for example, the seas were too high for an ALVIN launch.  ALVIN is launched from the stern of the Atlantis using a large winch to lift the sub and lower it into the water; if ALVIN is launched when the sea swells are too high, the ocean could pitch the sub back into the Atlantis as she's launched.  

A crane on the stern of a ship holds the deep submergence vehicle ALVIN poised above the sea as it about to be launched.
ALVIN being launched from the stern of the Atlantis. Photo © University of Washington, American Museum of Natural History, and Pennsylvania State University.

Weather conditions are also important eight hours after launch time; that's when the sub gets hoisted back onto the ship after a day's dive. If it is too dangerous to retrieve the sub, the ALVIN must remain bobbing in the ocean until the sea is calm enough for safe retrieval. The folks who conduct the launches are really well trained; they are super cautious about launching only when conditions are good. Weather permitting—and assuming everything else goes according to plan—it takes about two hours for the sub to descend to the bottom and position itself at the vent site after it is launched. The compartment is spherical; it looks like a giant silver ball, but its 14-inch-thick walls are made of a titanium-steel alloy. Titanium, iron, and carbon together create a very strong substance that stands up well to pressure and other deep sea conditions. Inside this ball, the three crew members (the pilot and two scientists) have about six feet (from wall to wall) in which to work, so it's pretty tight quarters for an eight-hour dive to the bottom and back.

Today, conditions at the surface of the sea were right, and we sent ALVIN off with a gentle splash a few hours ago. Now I'm on board, cataloging the tube worm samples collected yesterday; and in about four hours, the ALVIN will be back. When the ALVIN comes back up to the surface, it does take some time to get it back on board —about 45 minutes from when she reappears at the surface. We're all really excited to see the day's haul of samples and pictures, so it's always hard to wait till the ALVIN is back on deck. And it takes even longer if one of the crew members has gone down for the first time; the standard initiation for any new explorer is a whole pail of ice water (chilled specially in the cold rooms on the Atlantis) on the head!!  

After the fun's over, I'll let you know what they discovered at the deep sea vents today. And maybe one day soon, it'll be me with a pail of ice water on my head—I hope I get picked!

In calm seas,