Rocks bigger than basketballs were pushed into the ocean off San Clemente this week to provide the foundation for a 150-acre reef for giant kelp -- a project scientists say is one of the largest and most advanced in the world.
The artificial reef, to be made from roughly 125,000 tons of volcanic rock, is designed to anchor a swaying kelp forest, attract an array of marine creatures and help counteract the environmental destruction wrought by a nearby nuclear power plant.
After years of bureaucratic debate and delay, Southern California Edison is bankrolling the $40-million undertaking as part of an agreement with the state Coastal Commission.
The effort stems from a 1989 scientific report that found that the cloudy water discharged by the San Onofre Nuclear Generating Station's cooling system drifts south, blocking sunlight from a natural kelp bed and damaging about 180 acres of that habitat.
The reef will comprise puzzle-piece patches of rocks, their locations painstakingly planned through sonar measurements of water and sand depth; the rocks provide the hard surface kelp needs to flourish. Located more than half a mile offshore, the reef will stretch 2.5 miles roughly from San Clemente Pier to San Mateo Point, said Edison reef project manager Craig Eaker.
Key to the design is the loose arrangement of rocks in a single underwater layer, said Steve Schroeter, a research ecologist with the Marine Science Institute at UC Santa Barbara. This allows the rocks to jostle with the waves, flushing out competing species such as the pesky sea fan -- which takes longer to recover from swells -- and keeping space available for future generations of kelp. Other artificial kelp reefs, built with stacked rocks, have failed, Schroeter said.
Fast-growing kelp can shoot past 100 feet upward, drawing sea stars and sea urchins plus striped sand bass, yellowtail and halibut -- and the anglers who chase them.
"You're creating an . . . entire, complex marine ecosystem simply by laying down the foundation for the primary producers, the giant kelp," said David Kay, Edison's manager of environmental projects.
Aboard Edison's 25-foot cuddy boat Wednesday, bobbing alongside reef construction barges, Kay pulled up a stalk of the slimy, ocher-colored kelp. The plant's massive, bumpy leaves ruffled the water's surface, evidence of the thriving 22.4-acre experimental reef built in 1999 for scientists to observe how kelp best survived. Divers attached laboratory-grown young kelp plants to the sea bottom; these plants were quickly overtaken by natural kelp growth. (Google satellite images of these kelp patches appear as glowing red squares.)
