An autonomous underwater robot is set to open up exciting avenues of research in the deep sea by tracking elusive deep-sea creatures.
This new robotic vehicle is called the Mesobot which was developed by engineers and scientists from the Woods Hole Oceanographic Institution (WHOI), Monterey Bay Aquarium Research Institute (MBARI), Stanford University, and the University of Texas Rio Grande Valley.
Mesobot: The Underwater Robot
Mesobot had its first test in 2019 which was performed first in MBARI's test tank and then at sea when it was launch via the MBARI research vessel, Rachel Carson. The 250-kilogram robot is designed to track and study swimming and drifting animals in the ocean's twilight zone, or the mesopelagic zone that is 3,281 feet (1,000 meters) deep, without disturbing them.
The mesopelagic zone is the site of the diel vertical migration (DVM), the daily phenomenon when deep-sea creatures come closer to the surface for food but also dodging predators, according to New Scientist. It is where nutrients can be rapidly transported in the depths of the ocean where carbon dioxide is stored for the long term.
But studying DVM is tricky to study because creatures often flee from anything that disturbs the water or from when there is light. That is where the Mesobot comes.
According to MBARI's 2019 Annual Report, the underwater autonomous robot will extend previous midwater research by MBARI and other institutions. Mesobot will help better the understanding of the behavior and function of the mesopelagic zone.
It is designed to be less intrusive to deep-sea animals compared to most remotely operated underwater vehicles (ROV). Mesobot has low-light, ultra- high definition (4K) cameras, red lights which are less visible to deep-sea animals, and large, slow-turning propellers that minimize disturbances underwater.
Mesobot is a combination of an ROV, which is controlled and powered by a tether attached to a ship, and an autonomous underwater vehicle (AUV), which operates untethered without human intervention. Mesobot is operated tethered using fiber-optics at the beginning of the dive and then freed on its own as an AUV later on.
DVM in the Mesopelagic Zone
In 1942, a US Navy sonar looking for enemy submarines during World War II was puzzled when sonar images showed that the seafloor has changed its depth overnight.
According to Oceanus, WHOI's online publication, that the US Navy sonar operators later found out that the shifting seafloor is the mesopelagic zone where fish and other sea animals are making their nightly migration to and from the surface to feed.
It appeared that the ship's sonar is echoing off the gas-filled swim bladders of the animals, and since then scientists have primarily focused on acoustics in the form of sonar systems to peer into the mesopelagic zone and detect midwater animals.
Scientists also used nets and underwater camera systems to document the sea creatures, while some have even ventured into the ocean's twilight zone wearing the pressure-resistant submersibles to see these deep-sea creatures firsthand.
Each approach has its benefits and limitations and so scientists have come up with solutions, particularly using robots to study the ocean's twilight zone.
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