KQED: Massive California Kelp Decline Linked to Ocean Heat, Voracious Sea Urchins
Envision California’s lush forests from San Francisco to the Oregon border. Now imagine that 90 percent of those forests disappear within two years. Laura Rogers-Bennett, senior environmental scientist with the California Department of Fish and Wildlife, says that's exactly what happened to underwater kelp forests off Northern California’s coastline from 2014-16.
An analysis published this week in Scientific Reports documents the rapid decline of California’s bull kelp. The study links the reduction in the seaweed's population to a confluence of environmental and ecological stressors, including a marine heat wave, a sea star die-off and the emergence of an “urchin barrens,” large swaths of subtidal zones overtaken by kelp-hungry purple sea urchins.