Stuck in the Middle: Thin Layers of Phytoplankton

March Meeting 2010

Strong variations in marine currents form a watery trap for phytoplankton cells on their daily commute to the Ocean's surface.

Roman Stocker
Mack Durham

Massachusetts Institute of Technology (MIT)
Cambridge, Massachusetts 02139

John Kessler
University of Arizona
Tucson AZ 85721

Eric Climent
Institut de Mécanique des Fluides de Toulouse
31400 Toulouse

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Phytoplankton, small unicellular plants that live in the Ocean, are responsible for about one-half of the global production of oxygen and comprise the base of the marine food web. In a recent article in Science, we show that sharp changes in marine currents can trap swimming phytoplankton by causing them to overturn and tumble. These tiny swimming plants can swim into, but not out of these watery traps and can thus create intense aggregations of phytoplankton meters beneath the Ocean's surface. 

This new finding sheds light on many important marine processes including the cycling of chemicals through the Ocean, the productivity of marine fisheries, and the instigation of harmful phytoplankton blooms (aka red tides).


Durham, W. M., Kessler, J.O., and Stocker, R.  Disruption of vertical motility by shear triggers formation of thin phytoplankton layers.Science.3232009.

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