Word: oceaneering
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...swimming of a single jellyfish generates barely a ripple in the world's vast oceans. But what about a bloom of thousands of the creatures? Moving together, could they contribute to the large-scale mixing of ocean waters - the way the winds and tides do - as some scientist have long conjectured...
...research, published in the journal Nature, would suggest that the mass movement of marine animals - even tiny zooplankton like krill - may play a significant role in churning the ocean. It may help mix cooler water with warm, and disperse salts, nutrients and pollutants across the various layers of the ocean, which is critical to the strength of ocean currents and the health of the marine ecosystems. Although ocean-mixing is largely attributed to winds and ocean tides, scientists say those factors cannot account for all the energy required to power, for example, the complete circulation of cold and warm water...
...oceanographers familiar with the subject say research into ocean-mixing is only just beginning and that it's too early to make such assertions. "I appreciate what they [the Caltech team] are saying, but taking experiments of one particular event and extrapolating it to a global scale is always problematic," says oceanographer Andre Visser of the Technical University of Denmark...
...journal Science in 2006, a group of scientists reported that they had recorded enormous water turbulence in a fjord in Canada caused by a swarm of swimming krill. These tiny shrimplike organisms have a predictable up-and-down movement: during the day, they descend several hundred feet in the ocean, where there is less light and fewer predators; as the sun sets, they swim up to the surface to feed. Swarms of krill can be massive - some the size of Rhode Island - so oceanographers have suspected that their movements may cause significant ocean-mixing. But despite numerous attempts, the phenomenon...
...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...