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Man-made rock reef is part of a welcome seaweed change

Three years ago, Southern California Edison pushed basketball-size rocks from a barge off San Clemente. Little did the utility realize that the kelp reef it created would thrive the way it has, or as quickly.

By Tony Barboza

It was a gamble when Southern California Edison crews pushed basketball-size chunks of rock from a barge off San Clemente three years ago.

Eventually, the utility company hoped, the artificial reef it had assembled 50 feet below the waves would support a new kelp forest and fulfill state-imposed requirements to offset the damage its nearby nuclear power plant causes to marine life.

But no one expected the 174-acre Wheeler North Reef would thrive the way it has. Or as quickly.

Edison just happened to build its reef during the greatest giant kelp resurgence in decades, one that has brought an impressive buildup of floating green foliage to long-depleted waters near the Southern California shore.

"The last few years have been the most fantastic years for giant kelp in the last 30 years at least," said Nancy Caruso, a marine biologist who organized last month's Kelpfest in Laguna Beach, a festival celebrating the return of the underwater forests. "We had some excellent ocean conditions and the kelp started to spread, so they couldn't have timed it better."

More than a mere seaweed, giant kelp — a fast-growing algae — is the foundation for an entire ocean ecosystem, towering up from the seafloor to tangled canopies on the surface and offering nutrients and shelter to fish like sheepshead and perch as well as crabs, spiny lobsters and marine mammals.

Yet in recent decades, Southern California's kelp forests have been on the decline, reduced by up to 80% of their historic range.

Pollution from sewage and storm runoff has made it harder for sunlight to reach the leafy algae. As the kelp beds withered and the fish declined, sea urchins invaded the seafloor and crowded out the surviving kelp. Off San Onofre, the decline was accelerated by the warm, cloudy water discharged by the nuclear power plant.

Conservation groups have worked up and down the coast to try to restore kelp forests, planting seedlings and scattering spores in places such as Laguna Beach, Crystal Cove and Malibu, where there is a rocky seafloor for them to clamp onto. The results were initially disappointing as warm-water climate patterns such as El Niño continued to devastate the kelp.

Now, giant kelp has bounced back in the last few years, not because of made-man reefs but largely in response to a series of mild summers and an influx of cool, nutrient-rich water.

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