Alvin 2000: Dispatch 3

Thursday, April 13
Getting into Hot Water at the Bottom of the Sea

Hello again from the R/V Atlantis. We are steaming at 13 knots and have just reached 13 degrees north latitude. Only a few more degrees to go until we reach the dive site. Preparations are getting more intense. Our lab is completely set up and we are ready to get started. This morning we had a dry test of the water sampling bottles on the submarine. Not everything went right the first time, but this is why we did a dry run. By the end of our testing, all of the bottles were working.

There are many different ways to sample ocean water. The simplest, of course, is to throw a bucket over the side. But sampling deep hydrothermal fluids is a bit more of a technological challenge. Vents spew out water that could be 400 degrees Celcius and very acidic. Most materials will melt or degrade under these conditions. We have very special water bottles designed to take these temperatures as well as the harsh pressure conditions of the deep sea. These bottles were designed 20 years ago, specifically for the purpose of sampling hydrothermal vents, and many of the original bottles are still in use. The bottles (shown in the picture below) are machined from titanium with stainless steel fittings and screws. They work like big syringes.

The night before a dive, we fit the bottles with springs, and using the suction of a vacuum pump, pull the springs in tight. The next day, the pilots use a hydraulic ram on the mechanical arm of the submarine to push the triggers on the bottles. As the springs release, the piston of the bottle pulls back and the bottle chamber is filled with hot vent water. Sometimes the bottles are so hot you can see the heat shimmering off their sides. Metal bottles are necessary to take the heat of the vent fluids and rough conditions of a trip to the deep sea. However, not just any metal will do. Titanium is an expensive, but hearty metal that reduces the contamination of trace metals in our samples. As water chemists, one of our major tasks is keeping these bottles clean and in good working order. Every night, after we drain the samples out of the bottles, each bottle is disassembled and completely cleaned. It's a big task, but necessary to keeping the bottles in good condition.

That is all for now... tomorrow, if everything goes as planned, we should have exciting news about our first dive to the 9N site.

Other dispatches:

First dispatches from April 9th and 10th
Project overview and launch information!

Dispatch from April 12th
While heading out to dive area 9 North, the crew spots a few interesting sea animals. Much of the time is spent unpacking and testing equipment.

Dispatch from April 13th
Atlantis reaches 13 degrees latitude. Alison and crew test and retest the titanium collection bottles.

Dispatch from April 14th
The first dive of the expedition-Alison joins the crew! Researchers collect anenomes and fluids surrounding hydrothermal vents.

Dispatch from April 15th
Three dives have been completed. The day is spent retrieving cameras, analyzing hydrogen sulfide samples, and training new Alvin pilots.

Dispatch from April 17th
Not all time aboard Atlantis is work! Although shifts are often long, breaks allow for games and relaxation.

Dispatch from April 23rd
Temperature probes are placed near the vents. A lottery to join the crew of Alvin!

Dispatch from April 24th
The last dives of the trip...See how water pressure affects ordinary objects at extreme depths!

Dispatch from April 25th
This incredible voyage aboard Atlantis comes to an end. It's on to Mexico, and finally, back to New Hampshire to analyze our samples.