Deep Ocean Expeditions

In October 1999, I was part of the lecture team on the first Undersea Volcanoes of the Azores expedition. Using two MIR submersibles, each participant made a 9-hour dive to the Rainbow Hydrothermal Vents, located 8,000 feet down.

280 Miles SE of the Azores -
It was 9a.m. when I climbed into MIR I. My pilot was an old friend of 20 years, Dr Anatoly (Tolya) Sagalevitch director of the Manned Submersible Laboratory at the Moscow P.P. Shirshov Institute of Oceanology. Also along was Dr Fred McLaren, president of the Explorers Club. We had fine weather that day; the ships skilled topside handling team quickly had us off the deck of the Keldysh research ship and into the water.

Leaving the surface, a gradual loss of outside light indicated we were on our way down. As shades of grey gave way to total blackness, we settled in for the hour and a half trip to the seafloor, keeping busy by checking instruments and watching the intense marine life drifting by. Time went quickly.

About 1,000 feet above the ocean floor, Tolya turned on the fathometer to monitor the final part of our descent. Gradually we picked up a faint trace of the bottom as it 'moved up' to greet us. Now we could position ourselves in the 600-by-200 foot Rainbow Vent field.

The seafloor here was dotted with active and inactive smokers, many of which were several feet high. Finally I sighted the bottom and Tolya carefully brought the MIR to within a few feet of the seafloor. Now we would begin our five-hour 'flight' through the vent field.

MIR's giant external lights gave us a wonderful view of the area. My first impression was of a giant field of stone organ pipes. The largest were extinct smoker chimneys interspersed with the smaller active black smokers. When we flew through one of those hot black plumes you could feel the submersible rise in the 'thermal'. The water around the vents was loaded with particulate matter that continuously rained onto the seafloor.

Abundant marine life lived in the vicinity of the hot water plumes, a second life system entirely unknown until 22 years ago. Prior to that time the 'wisdom' was that all life on earth was derived from solar energy. Yet here on the deep seafloor, there lived a world independent of the sun, a life system whose energy came from chemical elements and thermal energy from the earth's interior. A variety of shrimps, mussels, crabs and fish lived a precarious existence in a narrow band between the scalding hot water from the vents and near freezing temperatures of the deep ocean around them - where the sea pressure is four tonnes per square inch!

All too soon our bottom time was over and Tolya signalled Keldysh that we were coming up. Content, we settled in for the trip back to the surface. It had been a great experience for me. Nearly 40 years ago, I had piloted the U.S. Navy bathyscaph Trieste to the bottom of the deepest trench on the ocean floor, the oldest seafloor on our planet. Now I had been to the other side, the spreading centre where seafloor was being created. With this dive to the edge of creation, I had completed my personal odyssey from 'alpha to omega'.

Don Walsh

azores.pdf ( 304Kb)