However, the new research shows that this is actually not the case and that the carbon is retained in deep-sea food webs. It had been thought that when the jellyfish sank to the seafloor they were essentially taken out of the system. This research has also prompted a fresh look at the role of jellyfish in the carbon cycle. Globally there are huge numbers of jellyfish in the ocean, and in some parts, jellyfish blooms are increasing, seemingly as a result of nutrient enrichment and a warming climate. However, as our video footage indicates, it seems that 'jelly-lakes' may be the exception rather than the rule and that jellyfish carcasses are consumed at speed by a host of deep-sea scavengers such as hagfish and crabs." The experiments were carried out in areas with jellyfish blooms near the ocean surface and showed that when the creatures fell to the seabed they were rapidly eaten by scavengers.ĭaniel Jones from the National Oceanography Centre, who is one of the authors of the study, explained: "In recent years, anecdotal studies have suggested that when jellyfish blooms die off, massive quantities of the creatures can sink to the ocean floor to form 'jelly-lakes', which are not eaten then simply rot, depleting the oxygen on the ocean floor and repelling fish and other sea creatures. Some bones were coated with pyrite, an indicator of high sulfur content, another characteristic common in modern whale-fall communities.Ĭretaceous seas were filled with many organisms that would look strange to a modern scuba diver, but this report seems to support that adage: The more things change, the more they stay the same.Researchers from the UK, Norway and Hawaii deployed lander systems to look at how scavengers responded to jellyfish and fish baits in the deep sea off Norway. Intimately associated with both skeletons were fossil snail shells of species closely related to snails found in nearby Cretaceous cold-seep fauna.Īlso, the bones were filled with channels and canals similar to those made by microorganisms in modern whalebones. One was a 26- to 39-foot-long elasmosaur and the other a 36-foot pliosaur. The report concerned two plesiosaur skeletons found in northern Japan. Plesiosaurs came in two varieties: pliosaurs, which had short necks and large skulls, superficially resembling killer whales and elasmosaurs, which had small heads on long necks. Plesiosaurs are just one group of reptiles that took to the high seas during the Mesozoic Era. That was long before whales evolved, so what was supplying large bones to the bottom of the sea? Plesiosaurs. Such whale-fall communities are known but rare in the fossil record, going back to some of the earliest whales 34 million years ago.Ī recent article in the journal Acta Palaeontologica Polonica extends the known record of such communities back to the Cretaceous Period 90 million years ago. Those snails often are close relatives of species that live around deep-sea vents, either hot ones (so-called "black smokers") or cool seeps, both of which also support large populations of bacteria and algae. Those microorganisms in turn are fed upon by larger animals, especially snails. The soft parts are consumed quickly, but the bones can remain for years, to be slowly eaten away by algae and bacteria that feed on the fats and oils in the bones. When a whale dies and sinks to the bottom of the ocean, its carcass provides a windfall of food for deep-sea organisms.
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