The Japan Agency for Marine-Earth Science And Technology (JAMSTEC), a Japanese research institute that is playing a leading role in deep-sea exploratory research around the world, has undertaken a round-the-world voyage on a quest for the limit of life using the manned research submersible SHINKAI 6500. In this, the 20th edition of Earthrium, we focus on this voyage, dubbed QUELLE 2013, as we consider the lofty goal of the institute's researchers to solve the riddle of the origins of the universe and life on earth.
In 2013, the Japanese manned research submersible SHINKAI 6500 and its support vessel YOKOSUKA set off on a round-the-world voyage during which they spent around a year exploring the habitable limits of life through a series of deep-sea surveys. The name of the project, "QUELLE," is an acronym of "Quest for the Limit of Life." Four deep-sea surveys (QUEST 1-4) were planned, with the third dive in the Caribbean Sea providing the opportunity for the first ever live broadcast from the cockpit of SHINKAI 6500 via the Internet.
QUELLE 2013 Project Leader Hiroshi Kitazato, recently returned from QUEST-2 (off Brazil), and QUEST-3 Chief Scientist Ken Takai spoke to Earthrium about their goals as researchers.
We left Yokosuka in Kanagawa Prefecture in January 2013 bound for the Central Indian Ridge and Rodrigues Triple Point area in the Indian Ocean. This area is a habitat for a snail with scales made of iron sulfides known as the scaly-foot gastropod.
One of our objectives was to attempt to understand how the scaly-foot gastropod produces the different materials that make up its iron armor. To achieve this we caught scaly-foot gastropods and kept them alive onboard while we conducted experiments to understand the mechanism whereby they form their shells, including the role of enzymes. If we could take them back to Japan and carry out further studies to find a microorganism capable of breaking down clean iron sulfides, it could lead to the development of technology to apply thin coatings of iron sulfides over the top of other material. In fact, however, all our specimens passed away within about a week of our returning to Japan (laughs). Although we extended our previous record as far as the length of their survival was concerned, it's incredibly difficult to keep them alive. However, we did manage to take some samples for analysis before they died, so we are currently analyzing those (Hiroshi Kitazato).
Between April and May of 2013, we crossed the South Atlantic Ocean from South Africa and carried out research off the coast of Brazil. We explored the Rio Grande Rise, an immense seamount that rises over 5000m from the ocean floor, and the Sao Paulo Plateau, where material derived from the earth's mantle is exposed on the sea floor.
This was the first time a manned submersible had ever entered this area of the South Atlantic. There is a large seamount there, and we made a number of discoveries, including finding deep-sea coral growing at the top of this seamount. Although it was not one of the objectives of this voyage, we also found under the sea a certain amount of granite, a rock that forms a major part of the continental crust. Unfortunately this was not the continent of Atlantis referred to by Plato. Rather, it was probably fragments of another continent that sunk. This may have been Pangaea, a supercontinent that existed long ago when Africa and South America were joined. As a result of this discovery, we now have to go back some 200 million years and explain the mechanism whereby large chunks of this continent ended up in this area. To find these large chunks of a continent was a complete surprise, and thinking about it fills me with a fresh sense of adventure (Hiroshi Kitazato).
In June 2013 we will survey the world's deepest hydrothermal vents in an area near the Cayman Islands, a British territory in the Caribbean Sea. It is said that hot water with a supercritical temperature in excess of 400°C issues forth from these vents. As well, three million years ago a land bridge connected South and North America, separating the Pacific and Atlantic Oceans. One of our objectives is to look at how organisms on either side evolved following the disappearance of this land bridge. During this voyage, we also plan to conduct a live Internet broadcast from SHINKAI 6500 while it is underwater.
There is a reason for carrying out deep-sea exploration in manned submersibles. Not only are there some scientific studies and other activities that can only be done with a manned submersible, but above all it is only when one actually goes underwater that one can get a real impression of what it is like. This time we want to share these impressions that researchers get when they go underwater aboard SHINKAI 6500 not via recorded images but in real time. We plan to use a fiber cable to connect the cockpit of SHINKAI 6500 where the pilots and the researcher sit with the support vessel, YOKOSUKA, and relay the footage live to Japan from YOKOSUKA via satellite. The result will prove that science can be the ultimate in entertainment. Of course, the fiber cable might break, ruining our plans, but such things are all part of the deep-sea exploration experience, and we are all looking forward to the challenge (Ken Takai).
After returning to Japan in August to replace SHINKAI 6500's batteries, the voyage will resume in October as we head for the Tonga and Kermadec trenches in the South Pacific Ocean. This will be the first exploration by JAMSTEC of the Tonga Trench, which is the second deepest in the world. JAMSTEC previously investigated the deepest known point in the Earth's seabed hydrosphere, the Challenger Deep in the Marianas Trench, and so the objective of this part of the voyage is to compare the ultra-deep-sea ecosystems of the deepest and second deepest locations.
As part of QUEST-4, we will find out what kinds of organisms inhabit the second deepest ocean floor in the world, what they do, and in particular how they contribute to the carbon cycle. We know that in the Tonga Trench material from the earth's interior (mantle material) is exposed. One of our objectives is to look for new chemosynthetic ecosystems there. As well, in the second half of QUEST-4 we will visit various seamounts and investigate a variety of ecosystems. We will observe how ecosystems in the vicinity of the Louisville Seamount Chain, which is subducting into the Tonga and Kermadec trenches, are changing. I am looking forward to using the majestic experiments the earth is conducting here to shed light on the ecology of deep-sea organisms (Hiroshi Kitazato).