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Pounding Surf

June 11, 2012

WHOI biologist Rebecca Gast steadies a coring tube as Bill Boyd, a senior engineer at Scripps Institution of Oceanography, drives it into the sand at Duck, North Carolina, while WHOI research associate Levi Gorrell looks on. After taking meter-long cores from several locations on the beach, Gast analyzed samples from different depths in each core for the presence of bacterial DNA. Working with WHOI physical oceanographers Steve Elgar and Britt Raubenheimer, she found that when sand moves—whether carried by tides, winds, or waves—it carries bacterial DNA with it. Their work suggests natural reshaping of a beach can redistribute microbes in the sand, including the indicator bacteria that lead to beach closures.(Photo by Steve Elgar, Woods Hole Oceanographic Institution)