Animals Abound

In addition to retrieving one of the thermocouple arrays, Dive 4557 brought a clump of tubeworms up from over 2000 meters below the ocean surface. This clump of worms the size of a soccer ball contained 18 small tubeworms and over 100 other smaller worms. We are interested in studying these creatures to understand how they thrive in such a variable and extreme environment that would be deadly to most animals living on the surface.

At the hydrothermal vents, the microbes that thrive on hydrogen sulfide provide the energy needed to support a prolific community of vent-associated animals. The quintessential vent animal is the tubeworm Riftia pachyptila. These animals have evolved to become completely dependent on symbiotic bacteria to provide them with nutrients. In fact, the worm is quite simplified and has a modified gut called a trophosome that is filled with cells that contain symbiotic bacteria. The worms simply need to supply the bacteria with hydrogen sulfide, nitrogen, and CO2 and the microbes use these simple building blocks to produce organic molecules that they share with their host. This teamwork strategy between the microbes and the tubeworm is highly successful allowing the worms to reach incredibly large sizes (some are over a meter long) and often these animals dominate areas around hydrothermal vents. Once you get over the grandeur of the tubeworm, you start to notice that there are a a lot of smaller creatures hanging around that are using similar strategies to survive in the deep ocean. Not surprisingly, there is a rich diversity of species in the vent communities that have figured out ways to either form direct partnerships with microbes or to live by eating the microbes or other animals.

Lauri's Guaymas Impressions:

12 November: Alvin's third dive was delayed for a few hours due to a technical issue, but eventually Mircea and Meg were sent on their way.

Pilot Mark's cool fisheye lens.

Up at the top lab, where Alvin and Atlantis communicate, I was surprised to hear how clearly voices travel through water, and with very little lag time.

We began production of the Best of Video DVD today, which will summarize the highlights of all the dives. There is some beautiful footage of the sea floor and what Fengping described as "massive dark lovely creatures shinning there, bubbling their story".

Alvin arrived at twilight, and brought with it many animal specimens such as tubeworms (and their hangers-on), more sulfides, and the thermalcouple array, which was coated with about eight inches of sulfide material and (hopefully) some microorganisms. The activity level really picks up in the evening, with processing continuing until well into the night.