Alvin 2000: Dispatch 8

Monday, April 24 - The final dives

We are wrapping up this cruise on the R/V Atlantis. We've had our last dives and are now packing up and heading for Manzanillo, Mexico.

Raoul, an ordinary seaman (OS) from Atlantis was the lucky winner of the crew lottery and was able to have an Alvin dive. He was nervous before going but completely enjoyed the experience. The crew helped him celebrate when he returned to the ship by dousing him with cold water, tossing him in the pool and presenting him with his tennis shoes, frozen solid in a block of ice.

Being nervous before an Alvin dive is certainly a common phenomenon. After all, each dive goes to ~2500 meters, with only the titanium sphere of Alvin to protect the divers from the crushing pressure of the ocean. A typical scuba dive has a maximum depth of only 100ft. The submersible goes much deeper...~8000 feet! A sphere is the ideal design for an submersible as the pressure of the water presses equally on all points, preventing an implosion. The divers sit safely in this sphere during the dive, completely protected from the outside environment. Alvin has three Plexiglas windows in the sphere so that we inside can see all of the exciting ocean floor outside but not be affected by the pressure. Alvin is pressure tested to deeper depths that we took it on this trip but the crush of the deep sea is always on our minds.

A fun souvenir of an Alvin dive can be made by coloring a Styrofoam cup with colored markers. (See close-up. Notice the difference in texture between the original and the compressed cups.) These cups are hung in a bag on the outside of the sub. The pressure of the deep ocean compresses the Styrofoam (squeezing out all the air spaces) and makes the cups much smaller than the original Styrofoam cup. These make great souvenirs, Christmas tree ornaments and gifts! Many cups have been shrunk on each dive this cruise.

We are very happy with the success of the water sampling. We got very good water samples that will keep the lab busy when we return to UNH. Hopefully analysis of these water samples will help us to answer more questions about the chemical and biological processes that occur at mid-ocean ridges.

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.