Global ocean map could increase safety, give early tsunami warnings: Shortwave: NPR

Global ocean map could increase safety, give early tsunami warnings: Shortwave: NPR

Cross-section map of Challenger Deep, the deepest point on Earth.

John Nelson/Ezri


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John Nelson/Ezri


Cross-section map of Challenger Deep, the deepest point on Earth.

John Nelson/Ezri

Life at the bottom of the ocean is extreme. It’s black, the temperature is hovering just above freezing and the pressure is enormous.

Although many species have evolved to survive and thrive at these depths, the seafloor is completely uninhabitable for humans. In fact, only a few dozen people have been able to reach the deepest part of the ocean floor, a place known as Challenger Deep.

A regular Styrofoam cup (L) is next to the Styrofoam cup that traveled to Challenger Deep and back (R).

Downright


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A regular Styrofoam cup (L) is next to the Styrofoam cup that traveled to Challenger Deep and back (R).

Downright

Marine geographer Dawn Wright is one of those people. “It’s a place that can be terrifying and terrifying or it can be infinitely wonderful and beautiful. For me, it was the latter.”

Wright is a senior scientist at the Environmental Systems Research Institute. It is also part of a global race to map the entire world’s oceans by 2030, which experts say is essential not only for pure scientific knowledge, but also for human safety and technological progress.

challenge accepted

When Wright joined Challenger Deep, it was exciting and full of purpose. As a marine geographer, she is interested in “rocks and movement on the ocean floor.”

Challenger Deep is located in the Pacific Ocean within the Marina Trench. It is 11,000 meters, or 6.7 miles, below the ocean’s surface. In July 2022, Wright and aviator and ocean explorer Victor Vescovo descended into a small submarine, then called a submarine. Limiting factor.

Wright likens the experience to being in a space capsule. “You’re in a very small space. You’re surrounded by devices,” she says. “We had a whole series of oxygen tanks on top of us because we had 96 hours of oxygen, which is extra oxygen that we take with us in case of an emergency.”

Dawn Wright (left) and Victor Vescovo (right) descend in a submarine into the Challenger Deep, the deepest part of the ocean.

Caladan Oceanic


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Caladan Oceanic


Dawn Wright (left) and Victor Vescovo (right) descend in a submarine into the Challenger Deep, the deepest part of the ocean.

Caladan Oceanic

Once they descended about 800 metres, they lost sunlight. “And it stays that way until the bottom,” says Wright. For her, this darkness made the fireworks show that they were about to see something even more amazing.

Worms, jellyfish, anglerfish — “these species are able to create their own light through bioluminescence,” she says. “They use light to find mates, hunt, and — apparently — try to communicate with submarines.” Victor noted. Flashes of light when we reached that area in the ocean. Then he began to direct the submarine’s lights toward them. “And we saw them flashing again.”

Aside from the fun of deep-sea creatures, Wright and Vescovo focused on testing a special mapping device.

Mapping the sea floor

If so few people reach the ocean floor, why do we need to map it? It’s less for road trips and more for, well, a lot Of other things. The most important of them are: monitoring and forecasting tsunamis.

This is because most tsunamis are the result of earthquakes that occur on the sea floor. “When you have this disturbance on the ocean floor, the water above the ocean floor is also severely disturbed,” Wright explains, which can generate large waves that can turn into tsunamis.

By mapping the sea floor, scientists can identify and monitor underwater areas prone to earthquakes. This could give coastal areas longer to warn in the event of a tsunami.

The ocean floor also serves as an important site for human innovations. For example, intercontinental submarine cables account for the vast majority of our Internet traffic. Offshore wind farm developers also need to know the composition of the seabed to install turbines.

Mapping the ocean floor may also help protect vulnerable marine habitats, or help find people and objects lost at sea.

Historically, satellite data has been key to mapping the ocean, but Wright says those maps are too blurry to see fine detail.

the solution? Voice navigation and ranging or sonar.

“It’s like you’re getting a new prescription for glasses,” she says. “Everything is in focus, and you see things clearly.”

The basic principle of sonar mapping is that the ship or instrument sends sound pulses from the ocean surface down toward the sea floor and waits for them to come back up. Depending on the amount of time it takes for sound to return and factors such as temperature and salt content, scientists can get a specific depth. Hence, surveying an entire area of ​​the sea floor will give you a depth map or bathymetry. In the same way that a topographic map shows changes in elevation, a bathymetric map shows changes in depth.

Seabed 2030

Only about 25% of the world’s seafloor is currently mapped in detail, but an initiative called Seabed 2030 aims to reach 100% in just over six years. The mission, led by the Nippon Foundation and GEBCO, may seem daunting, but Wright says that just a few years ago, only about 6% of the ocean floor had been mapped.

To complete the picture, ocean mappers are looking to industry to fill some gaps. “The hope is that we can get to 40 percent very quickly if we can get a lot of these companies to release their data and make it public,” Wright says.

If the entire ocean floor is not mapped by 2030 — one of several goals of the United Nations Decade of Ocean Science for Sustainable Development — Wright says the work will continue. But she adds: “The longer it takes us to get close to 100 percent, for all the reasons we talked about, we will be playing with fire, so to speak.”

Are you curious about ocean science? Email us at shortwave@npr.org.

Listen to shortwave on Spotify, Apple Podcast And Google Podcast.

This episode was produced by Pearly McCoy, edited by Rebecca Ramirez, and fact-checked by Anil Oza and Rebecca. Robert Rodriguez was the sound engineer.

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