Thursday, July 30, 2009

ocean mixing by jellyfish

I love the ocean-mixing paper in today's issue of Nature (and on the cover). Essentially, researchers believe that turbulence created by fish swimming around doesn't do much for ocean mixing (as it's limited to small scale and gets lost in friction), but the authors find evidence for surprisingly large mixing effects simply from the layers of water that a swimming organism drags along (details depending on its shape, and the viscosity of the water).

This mechanism was first considered in 1953 by the grandson of Charles Darwin, who is confusingly also called Charles Darwin (the authors of the Nature paper never bother to tell us that it is not the Darwin they are talking about!).

Understanding ocean mixing is especially important today in the context of climate change, as the oceans have a much higher heat capacity than the atmosphere. They also store more carbon, and are instrumental in natural processes of carbon sequestration (e.g. calcite sediments).

Im just a bit worried what creationists will make of this story. Soon they will be telling us that the big bearded guy put jellyfish in the oceans to ensure proper mixing ...

ref:

Kakani Katija & John O. Dabiri
A viscosity-enhanced mechanism for biogenic ocean mixing
Nature 460, 624-626 (30 July 2009) | doi:10.1038/nature08207

News & Views by William Dewar on page 581

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