Every spring, the waters of the North Atlantic revive as the days lengthen and phytoplankton explode in number.
For decades, scientists therefore thought they understood what sets off the annual phytoplankton bloom: spring sunshine. But a study published this month in Science upends the prevailing view, reporting that shallow ocean currents kick-start the seasonal phenomenon. The researchers found that the eddies cause the phytoplankton to start blooming two to three weeks earlier than it would if it were reacting solely to longer days.
The bloom cycle is critical because phytoplankton provides food for a vast network of aquatic creatures in the North Atlantic.
“The entire food web is based on phytoplankton,” said Mary Jane Perry, an oceanographer at the University of Maine and one of the paper’s authors. “We jokingly say, ‘No phytoplankton, no zooplankton. No zooplankton, no fish.’ ”