SF Gate: Purple sea urchins spoiling kelp forest
Below the gently rolling waves off the Palos Verdes Peninsula, a spiny purple menace is ravaging what should be a thriving kelp forest.
Millions of sea urchins - scrawny, diseased and desperate for food - have overrun a band of the shallow seafloor, devouring kelp and crowding out most all other life at a time the giant green foliage is making a comeback elsewhere along the California coast.
In an effort to remedy the situation, scientists and divers will spend the next five years culling the urchins from more than 152 acres of coastal waters degraded years ago by pollution. Once the purple, golf ball-size creatures are under control, young kelp should be able to take hold on the rocky seafloor and grow into the undulating canopies that sustain hundreds of species of marine life.