The largest migration On earth are not some herbivores in Africa or A bird in the sky,but vertical The movement of the entire ecosystem on the high seas. During the day, all kinds of animals, from fish to crustaceans, wander in the depths, where darkness protects people from predators. At night, they migrate to the shallows for food. Then, when the sun rises, they swim back to where they were-this is a huge biomass conveyor belt.

But now a spy is swimming among them: Mesobot.Today in the magazine Scientific robot, A team of engineers and oceanographers description How do they get a new autonomous underwater vehicle to lock the movement of organisms and follow them around the ocean”Fuzzy zone, “A Long understudied The zone from 650 feet to 3,200 feet deep is also called midwater by scientists. Thanks to some ingenious engineering, the researchers did not panic these highly sensitive animals, making Mesobot a pioneering new tool for oceanographers.

“From an engineering point of view, this is very cool,” said Hanumant Singh, a robotics expert at Northeastern University. Develop marine robots But did not participate in this research. “In terms of observing the undeveloped areas in the ocean, this is indeed an amazing job.”

Mesobot looks like a huge yellow-black AirPods shell, but it is more waterproof and weighs 550 pounds. It can be operated using an optical fiber tether connected to a surface research ship, or it can swim freely.

Video: Erik Olsen/Woods Hole Oceanographic Institution

Mesobot’s first ingenious project was its propulsion system-a large, slow-moving propeller that can produce low-speed jets. “Why are we so worried about disturbing water sources?” asked Dana Yoerger, a senior scientist at the Woods Hole Oceanographic Institution and the first author of the paper. “Most mid-water animals are extremely sensitive to any hydrodynamic disturbance. Because normally, this is what eats them.” If you disturb these animals, you will not observe their natural behavior. (Unless you are curious about what annoys them.)

The second clever trick ensures that Mesobot does not disturb its objects by shining them with light. Well, at least not white light. Yoerger and his team chose the red beam because it cannot penetrate the sea water well. “Evolution doesn’t waste a lot of power on things that don’t work well, so most animals turn a blind eye to red light,” Yoerger said. This is why when you see bioluminescent creatures appearing in the deep ocean, they are blue or green. “We use red,” Yoerger continued. “Although red is very bad because it doesn’t go very far. It doesn’t scare animals so much. This is well documented. So this is a tradeoff: you need a lot Light, you need a sensitive camera, and then you can work in red.”

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