ScienceDaily (Nov. 23, 2009) — Understanding mixing in the ocean is of fundamental importance to modeling climate change or predicting the effects of an El Niño on our weather. Modern ocean models primarily incorporate the effects of winds and tides. However, they do not generally take into account the mixing generated by swimming animals.

More than 60 years ago, oceanographers predicted that the effect of swimming animals could be profound. Accounting for this effort has proven difficult, though, so it has not entered into today's models.

Now Kakani Katija and John Dabiri at the California Institute of Technology have developed a way to estimate the extent of "biogenic" mixing. After conducting field measurements on swimming jellyfish, they built models of how animals mix the waters ocean-wide and concluded that the effect may be extensive.

"Swimming animals may contribute to ocean mixing on the same level as winds and tides," says Katija. "This necessitates the inclusion of biogenic mixing sources in ocean circulation and global climate models."

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