10 Recent Breakthroughs in Marine Biology

Scavengers of the Deep Dig Dead Jellyfish After All
Sure, sea turtles enjoy jellyfish, but what about seafloor scavengers? Reinhard Dirscherl/ullstein bild via Getty Images

Jellyfish have long been a source of concern for swimmers, fish farmers and any machine with an oceanic intake. But they've more recently become a headache for oceanographers, who must puzzle out why jellyfish blooms are on the rise, and how that rise threatens to upset the balance of life in Earth's oceans -- and that's just among the living [sources: Flannery; Gorman]. Because dead jellyfish apparently pose a problem as well: When large die-offs occur, it appears that their bodies just jelly up the ocean floor, where scavengers seemingly turn up their collective noses at them [sources: Gorman]. Or so we thought.

Thanks to experiments conducted by Andrew Sweetman of the International Research Institute of Stavanger and his colleagues, published in the December 2014 issue of Proceedings of the Royal Society B, we now know that scavengers such as crabs and hagfish actually chow down on jellies with at least as much relish as they do mackerel. This is important, because it means that jellyfish are an integral part of the carbon cycle, and not some kind of carrion cul-de-sac [sources: Gorman; Sweetman et al.].

So why the mix-up? It's possible that previous observations only caught mass die-offs and/or that observations took place in areas that lacked jelly-eating scavengers. In other areas, the rapidity with which jellyfish are eaten (around two hours, in the experiment) might have removed any contrasting cases before they would have been observed [sources: Gorman; Sweetman et al.].

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