Last October, I dove nearly 8,000 feet to the floor of the Atlantic Ocean in the Russian research submersible Mir 1. The site was the Rainbow Vents on the mid-ocean ridge near the Azores. This area of hydrothermal vents is part of the 40,000mile-long mid-ocean ridge system that girdles the globe, perhaps the single largest geographic feature on our planet. The only evidence of this system we can see are a few "mountain peaks" poking through the ocean's surface. We call them "islands."
According to the theory of "plate tectonics," the earth's surface is made up of some 16 major crustal plates that are in constant motion. The plate boundaries are geologically active through three primary processes. At some places the plates slide past each other—California's San Andreas Fault line is an example of this motion. At other boundaries, seafloor plate material is being "consumed" when the moving seafloor plate collides with another plate edge. Here, one of the plates is pushed down into the interior of the earth where it is eventually recycled. The buckling of the seafloor in these collision areas results in huge "wrinkles," or trenches, on the seafloor; these are the deepest places in the oceans. The third process is "seafloor spreading," where new seafloor crust is being created. The mid-ocean ridge in the Atlantic is an example of this, This is the "edge of creation"—the place where new planetary crust is just a few minutes old in geological terms.
Hydrothermal vents are created along spreading centers when seawater percolates into the sub-seafloor rock structure and is superheated by molten rock beneath the surface. The water is superheated to temperatures as high as 600'F and jets out from the seafloor. As the water passes through the rocky strata below the surface it often leaches out metallic compounds. The result is "black smokers," chimneys made up of metallic-rich compounds that have precipitated as they hit the cold seawater. Hydrothermal vents come in patches covering rather small areas. They are transient features, with vents starting up and others shutting down over time. The Rainbow Vents were discovered in 1997, and now cover an area of about 600 by 200 feet. First discovered by a British expedition, French and Russian oceanographers have dived on them using manned submersibles. "Rainbow" refers to the diverse coloration of the smoker chimneys and bottom sediments in the area that results from the metallic sulphides discharged.
Also present at these vents was a great quantity of marine life. Shrimps, mussels, fish, and crabs were the most evident—though there were many other life forms too numerous to list here. All of this life was independent of the ocean's surface and solar energy. Instead of photosynthesis, which fuels life up on our planet's outer skin, these organisms were 11 chemosynthetic." That is, they derive their life-supporting energy from thermal energy and chemical compounds from the earth's interior. To some extent, we were visiting another planet when we were at this site. Furthermore, the existence of this second complete life system on earth was not even known until 20 years ago. The manned submersible Alvin first saw this life in the sea during a 1979 expedition to a spreading center in the Pacific.
This "research expedition" was a bit different from the way marine science is usually conducted at sea. The Keldysh had 12 Russian oceanographers on board, but the expedition was paid for by 14 foreign tourists who wanted the experience of diving in this area. Each paid $18,000 for the 12day expedition, which included one nine-hour dive to the vents. But science got done. On each of the 16 dives made at the site the submersible pilots would take geological, biological, and water samples. In addition, complete imagery of each seafloor track was taken by external still and video cameras. And at night when the submersibles were on deck, the ship would do standard oceanographic work. Perhaps the most interesting work for the participants was using the deep trawls to sample marine life a mile beneath the ship. There was always a nice crowd hanging around the aft deck when the trawls came back on board. Sort of a biologists "Christmas package."
This expedition was one of those very rare examples where support came from private instead of government funding. The model seemed to work, and the Russian scientists were very happy with the results. One of their fish biologists told me that this was the first time his laboratory bad collected deep-ocean specimens in ten years (since the end of the Soviet Union). In fact the model was so successful for both tourists and Russian oceanographers that there will be two of these expeditions in 2000. 1 already have arranged to be there.
For me this expedition was the end of a personal journey from Alpha to Omega. Forty years ago, I copiloted the Trieste to the floor of the deepest trench in the ocean, the place where earth's crust is being destroyed. In October, the Mir 1 took me to the other end of the "system" where the crust is being created.