by Sadly, the Secret of JOIDES, also known as the JR, may have sent for the last time. On August 2, 2024, it set sail in Amsterdam, with no clear path to raise the US$72 million per year needed to operate the vessel. Most of this funding comes from the US National Science Foundation, which announced in 2023 that it would not fund the JR after 2024 because contributions from international partners were not keeping up with rising costs. Crews have begun removing scientific equipment from the ship.
The National Science Foundation says it will support ongoing research using existing core samples and work with scientists to plan the future of scientific ocean drilling. But in my opinion and many other scientists, the cost of operating JR is small compared to the damage caused by a single large earthquake – such as Japan’s 2011 Tohuku-Oki earthquake, estimated at $220 billion – or the trillion dollars in damages resulting from the climate. change. Core ocean research helps scientists understand events like this so societies can plan for the future.
A floating laboratory
No other vessel has the capabilities of the JR. The ship is 469 feet (143 meters) long – 50% longer than a football field. It has more than 5 miles (8 kilometers) of drill pipe that connects the ship to the seabed and the layers below it, allowing it to lift core samples from the submarine to the ship.
The JR’s dynamic positioning system enables it to remain stationary in one location for days or weeks at a time. Only two other ships in the world have this capability: the Chikyu, a larger vessel operated by Japan in Japanese waters, and a new Chinese drill ship called the Mengxiang.
I have spent eight two-month expeditions on the JOIDES Mission, mainly at high latitudes near the poles exploring past climates. There was a team of about 60 scientists and technicians and 65 staff members in each trip. Once the ship left port, operations ran 24 hours a day, every day. We all worked 12 hour shifts.
These journeys could be cruel. Usually, however, the excitement of new and often unexpected discoveries, and friendships with fellow participants, made the time go faster.
Insights from JR’s travels
As early as the 1960s, geologists began to realize that the Earth’s continents and oceans were not static. Rather, they are part of moving plates within the Earth’s crust and upper mantle. The movement of the plates, especially when they collide with each other, causes earthquakes and volcanoes.
Marine sediment cores can penetrate a mile or more into the Earth’s crust. They provide the only opportunity to investigate ongoing changes in the interactions of tectonic plates, study the evolution of climate and oceans, and explore the limits of terrestrial life. Here are four areas where the details of these processes began to emerge:
Plate tectonic formation
The oceanic crust is fundamentally different from the crust that lies beneath the continents. When I first learned about this in the 1970s, the model for its formation and structure was simple:
– Lava rose from the magma chambers beneath the ocean floor volcanic chains, known as ocean ridges.
– It poured out onto the sea floor, creating a dark, often glassy volcanic rock called basalt.
– Within the deeper, slowly cooling magma chamber, crystalline minerals formed, creating rocks with a granite-like texture.
– Over millions of years, this new crust moved away from the ridges, becoming cooler and denser.
But cores recovered by the Secret of JOIDES, as well as studies using underwater robots known as submersibles, showed this view to be inaccurate. For example, they showed that seawater diffuses through the crust, changing its composition and the chemistry of the seawater itself.
Key studies have also shown that the Earth’s mantle – a foundation thought to lie deep below the surface – moves along previously unknown giant fault zones and extends up to the surface of the oceanic crust. The mantle may provide clues to the origins of life.
These insights changed scientists’ fundamental understanding of the structure of our planet.
Climatic records in oceanic crust
My particular interest is in sediments that accumulate on the ocean crust. These deposits contain tiny microfossils of plankton, including organisms such as diatoms and coccolithophores that live on or near the ocean surface. As they photosynthesize, they absorb carbon dioxide from the atmosphere and produce half of all the oxygen we breathe.
Plankton types vary according to the temperature and chemistry of the seawater. When they die and sink to the bottom of the sea, they preserve an amazing record of past climates. Scientists use them to understand how Earth’s climate has warmed and cooled in the past.
Another source of information is sediment that falls from melting icebergs. Glaciers build rocks as they flow over land. When they reach the sea, parts of them break off to become icebergs. The ice melts when exposed to warmer ocean water, and the rocks fall to the bottom of the sea. These rock deposits in sediments are a record of past transitions between warm and cold climates.
Destruction of plates and recycling
Most of the Pacific Ocean and some regions of the Atlantic Ocean lie over zones called convergent edges, where tectonic plates are crunching against each other. This process leaves some oceanic crust and sediment down into the Earth, where it melts and is eventually recycled into new crust, often as volcanoes.
Massive faults along these edges can cause massive earthquakes, such as the 2011 Tohoku-Oki earthquake off the east coast of Japan. Cores taken near such faults help scientists understand the forces that cause these events. They also create openings where instruments can be inserted to monitor for future earthquakes.
Cores recovered from convergent margin zones have begun to reveal how volcanoes are formed and how they modulate long-term climate change by producing carbon dioxide emissions.
The limits of terrestrial life
In the late 1970s, new exotic forms of land life were discovered in the Pacific Ocean at areas where oceanic crust formed. At plate boundaries, cold sea water seeps down through cracks in the crust. Then, hot magma reheated it and rose through openings that scientists named hydrothermal vents.
There were minerals in the hot water, which cooled when they came into contact with the cold sea water and hardened into chimney structures around the vents. Hundreds of life forms, including microbes, mussels and tube worms, have colonized these structures, thriving near zones of intense pressure and temperatures as hot as 248 degrees Fahrenheit (120 Celsius).
JR coring has subsequently revealed other life forms that live deep in the sub-ocean floor, in conditions of extreme oxygen and energy deprivation. Scientists know almost nothing about the diversity of these organisms, or the metabolic strategies they use to survive in their challenging environment. Understanding how they succeed could inform missions to other planets, such as Saturn’s moon Enceladus and Jupiter’s moon Europa, which have subsurface oceans that could support life.
What’s next for scientific sea drilling?
The National Science Foundation has created a committee to consider what capabilities a new drill ship should have, and Congress may provide funding for additional JR trips in 2025. Because how much scientists don’t know still about the history of the Earth, and the challenges facing humanity. Adapting to climate change, I and my colleagues hope that the JOIDES Secret can still sail again, and that a new ship will eventually take up its mission.
This article is republished from The Conversation, a non-profit, independent news organization that brings you facts and analysis to help you make sense of our complex world.
Written by: Suzanne O’Connell, Wesleyan University.
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Suzanne O’Connell does not work for, consult with, share in, or be funded by any company or organization that would benefit from this article, and she does not disclose any relevant connections beyond her academic appointment.
