A number of questions have inspired marine ecologist Stuart Sandin to head to the coral reefs of the Line Islands. Sandin works at the Scripps Institution of Oceanography at the University of California, San Diego. In this video he explains why the structure of coral reefs matters and how human activity can impact it. Read his blog post about why on healthy reefs far from people, you see far more sharks and other top predators than you'd expect.
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