IN 2013, CALIFORNIA’S BULL KELP forests began a vanishing act. First, the starfish blinked out, their tissue decaying in lesions until their arms fell off their bodies like petals. Next, the purple urchins multiplied in vast hordes like a glitch in the system, munching steadily on bull kelp until it had all but disappeared. All this time, the water kept warming, with temperatures hovering around 2.5 degrees Celsius above normal. Once the kelp was gone, the red abalone starved, leaving behind an underwater graveyard of upturned shells. But millions of urchins stuck around, carpeting the seafloor like violet-colored burrs.
You can also learn more about the Palos Verdes kelp reforestation project, which is the best example of how we can quickly and effectively restore California's kelp forests.