Regional Interests A Sea Urchin Army Is Mowing Down California’s Kelp Forests — But Why? KQED Published July 19, 2018 at 8:05 PM PDT Twitter LinkedIn Email Kelp is a keystone in the ocean ecosystem. It's not entirely clear why the urchins have taken over, but there's optimism that the kelp devastation is temporary. Copyright 2018 KQED