July 30, 2009

Study: Jellyfish help oceans mix it up

Jellyfish and other small swimming marine creatures can have a huge impact on ocean mixing, researchers in California report.

Increasingly, scientists have been thinking about the possible role ocean animals may play in larger-scale ocean mixing, the process by which layers of water interact to distribute heat, nutrients and gases throughout the oceans, California Institute of Technology researchers said Thursday in a release.

The perspective we usually take is how the ocean -- by its currents, temperature, and chemistry -- is affecting animals, says John Dabiri, a Caltech bio-engineer who, along with Caltech graduate student Kakani Katija, discovered the new mechanism. But there have been increasing suggestions that the inverse is also important, how the animals themselves, via swimming, might impact the ocean environment.

Dabiri's and Katija's findings indicating the inverse to be true were published in Thursday's issue of Nature.

Dabiri said oceanographers had dismissed the idea that animals having a significant effect on ocean mixing, believing that the viscosity of water would balance out any turbulence created by small, drifting, animals.

Results from this study will change some of our long-held conceptions about mixing processes in the oceans, says David Garrison, director of the National Science Foundation's biological oceanography program, which funded the research.