Don't Underestimate the Small Stuff

Complexity In the Field
J.B. Ruhl
October 18, 2006

Any thought that the "small stuff" doesn't matter ought to be dispelled by this recent news of a study focusing on the mixing effect of phytoplankton and other organisms swimming in the ocean--a perfect example of cumulative effects extending from the microscopic scale to the global scale:

Physical and biological oceanographers led by FSU Professor William Dewar have found that the marine biosphere -- the chain of sea life anchored by phytoplankton -- invests around one percent (1 terawatt) of its chemical power fortune in mechanical energy, which is manifested in the swimming motions of hungry ocean swimmers ranging from whales and fish to shrimp and krill. Those swimming motions mix the water much as cream is stirred into coffee by swiping a spoon through it. And the sum of all that phytoplankton-fueled stirring may equal climate control. "By interpreting existing data in a different way, we have predicted theoretically that the amount of mixing caused by ocean swimmers is comparable to the deep ocean mixing caused by the wind blowing on the ocean surface and the effects of the tides," Dewar said.

In fact, he explained, biosphere mixing appears to provide about one third the power required to bring the deep, cold waters of the world ocean to the surface, which in turn completes the ocean's conveyor belt circulation critical to the global climate system. Along with the new calculations that point to the marine biosphere's bigger-than-expected role in ocean mixing and climate control, Dewar and his colleagues also suggest that human and environmental decimation of whale and big fish populations may have had a measurable impact on the total biomixing occurring in the world's oceans.

Findings from the FSU-led study ("Does the marine biosphere mix the ocean?") will appear in the forthcoming issue of the Journal of Marine Research, adding the role of major power broker to phytoplankton's already impressive credentials.

I suppose one solution would be to encourage people to swim in the ocean more often.