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Lost City Expedition: Science

The Discovery of the Lost City Hydrothermal Field, 2000

Leaps in science sometimes occur serendipitously—people are in the right place at the right time, they have worked on different pieces of a puzzle and then something seemingly unconnected happens that makes all the pieces come together and an important discovery is made. So it was with the discovery of the Lost City Hydrothermal Field. In 2000, Kelley, Karson, and Früh-Green participated on a cruise to the Atlantis massif, which was lead by Donna Blackman, Scripps Institution of Oceanography. The goal of that expedition ( was to investigate how the Atlantis mountain was formed and altered during its 2 million year history.

On December 4th, nearly at the end of the Blackman expedition, Gretchen Früh-Green and Barbara John (University of Wyoming) were in the control room for the remotely operated camera system called Argo. This camera system, tethered to the ship by a fiber optic cable, sent video and digital still images back to the ship. It was used to image the large cliff faces and to investigate the fractured outcrop of mantle rocks that are common beneath the field. Late in the evening, Barbara, Gretchen and the operations group in the control room came upon a landscape unlike anything anybody had observed before. Gretchen came running excitedly into the cabin Karson and Kelley were meeting in and shared her excitement that “something” had been discovered, which she thought wa a new kind of hydrothermal chimney. Kelley and Karson joined the clamor in the control room and also witnessed the amazing discovery of the Lost City Field. They, along with other members of the science party, stayed into the very early morning using Argo to view as much of the field as possible and to gain insights into how to explore the field during a follow-on Alvin dive one day later.

The evening was filled with excitement, anxiousness, and much discussion about exactly what we were seeing. It is hard to convey what an amazing job the Argo team did “flying” the camera up, over and around the clusters of steep pinnacles that reached > 30 m (> 90 feet) above the seafloor. To get an idea of the skill that this group has, try placing an object at the bottom of a bucket of water and then lowering a lightly weighted string to the bottom-go around the object as close as you can without touching it. Then imagine that this string extends to a depth <2000 feet beneath the surface of the ocean, that the string is tugged up and down due to the action of the waves and the ship at the surface, and that the only part of the seafloor that you can see is that lit by a few lights on the camera sled. During the game you must maneuver the string around the object, up steep vertical and overhanging cliffs, but you are not allowed to touch the rock. This is what the pilots and navigation specialists did for several entrancing hours during the discovery of the field.

The First “Live” Visit
Part of being at sea and working on complex programs involves making difficult decisions—one of those decisions was who would dive on the field. The discovery of the field was a group effort that included all of the crew of the Atlantis, Argo, and the science team—we were in the right place at the right time, and had people who recognized “something different and extraordinary”. When it came to who would dive on the field, however, only three people could go first: Karson, Kelley, and the Expedition leader and chief pilot of Alvin, Pat Hickey, were chosen to go because they had the most experience working on the seafloor and with submarine hydrothermal systems.

During the day of December 4th, many people worked over the imagery collected during the Argo dive, and planned a strategy to explore the Lost City Field. The Alvin dive occurred on a very windy morning on December 5th, which started late due to periodic squalls that made it difficult to put Alvin in the water. Finally, however, Deb, Jeff and Pat rapidly descended to the seafloor in Alvin-reaching it within 1/2 hour. They landed a few hundred meters beneath the field, and Pat worked his way up overhanging ledges to the field. We were all anxious because we knew we only had one dive to get fluid, rock, and fauna samples and map out as much of the field as possible. The discoveries from that single dive provided the framework for this cruise nearly three years later…and they continue to show us that there is much yet to be discovered about the inner space that makes up our oceans.