Word: jellyfish
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Kakani Katija, a graduate student at the California Institute of Technology, believes it's possible, based on her recent experiments with jellyfish blooms in a freshwater lake in Palau. Using high-powered underwater lasers and video cameras, Katija and her team studied how the movement of jellyfish impacts the water around them. Researchers placed a fluorescent dye in front of the jellyfish and observed what happened as the jellyfish swam through it. To their surprise, rather than swimming through the dye, the jellyfish appeared to pick it up, tucking it in a space just behind their tentacles. As the jellyfish...
...high-pressure field is created in front of the body, and a low-pressure field is created at the back of the body," explains Katija, and the low-pressure acts like a vacuum, sucking in the nearby water when the jellyfish begins to move. "What we have found is a mechanism that would allow for animals to mix water efficiently when they swim...
...part, Gregg is hoping to study mixing by following fishing trawlers, since good fishing grounds are usually the places with lots of ocean churn. Meanwhile immense blooms of jellyfish - of the kind that Katija studied - are drawing the attention of other scientists and policymakers. Such blooms, thousands strong, are becoming increasingly common worldwide, in part due to the overfishing of jellyfish's natural predators, including anchovies, sardines and herring. In the Sea of Japan, for example, the nomura, jellyfish that grow up to 6.5 ft. (2 m) in diameter and weigh more than 400 lbs. (180 kg), have proliferated...
Whether or not they contribute to ocean-mixing, it's clear that mushrooming swarms of jellyfish can threaten marine ecosystems by competing with native fish, spread aquatic parasites and contaminate commercial-fishing catches. We could be very close to a stage where parts of the ocean "go from being dominated by fish to being dominated by jellyfish," says marine ecologist Anthony Richardson of the University of Queensland in Australia. "And once we're on this jellyfish joyride, it is extremely difficult...
...Read "When Jellyfish Attack...