Undersea restoration
An artificial reef off San Clemente is now barren of its kelp, but scientists say that's part of the natural cycle. A long-term effort to restore the underwater forest continues.
The Orange County Register
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SAN CLEMENTE COAST – The boat pitched up and down on waves big enough to give even a seasoned marine scientist the stomach jitters, and the dense fog didn't help.
At last, Patrick Tennant, a biologist with Southern California Edison, reached the spot he'd been looking for. The radar picture showed a series of squares on the ocean floor.
Soon he caught sight of two boats full of divers preparing to drop into the depths and take surveys of marine organisms at the bottom.
Tennant is the keeper of Edison's artificial kelp reef, meant to make up for damage to kelp habitat caused by the San Onofre nuclear plant.
The project, begun in 1999, has cost $19 million so far, not including a 15-year, $50 million study that preceded it. Edison expects to spend another $27 million before the 150-acre reef is finished.
The squares are piles of rock and concrete, intended as attachment sites for kelp strands.
But there was one thing Tennant knew he would not find that day: kelp. There wasn't a trace of it on the surface.
The divers found only a scattering of tiny kelp "plants" on the rocks below.
"There was really such a canopy just a year ago," Tennant said. "Now there's hardly any at all – just because of ocean conditions."
The variable quality of giant kelp, which can grow into thick marine forests that are refuges for a variety of species, is well known to those who spend their lives trying to make it grow.
When the water's too warm, the kelp can fade away. When it's cold, the kelp strands, anchored to rocks on the bottom, can grow to more than 50 feet as they reach for sunlight at the surface.
That is true up and down the Southern California coast, where kelp can grow thick and remain intact for several years, then completely vanish in a season.
This year giant kelp seems to be absent from the surface along much of the Orange and San Diego county coasts, despite strong growth for the past six years.
Warm water is a likely cause. Last year's thick and persistent red tide, which lingered for months, also might have left young kelp at the bottom starved of sunlight.
"My sense is, the kelps are not in bad trouble," said Paul Dayton, a marine ecologist at the Scripps Institution of Oceanography. "But the surface canopy is fading."
The scientists preparing to expand Edison's artificial reef are confident the kelp will return.
Ecologist Steve Schroeter and his scientific crew from UC Santa Barbara have been making detailed observations of marine organisms that crawl on or cling to the reef, made of squares, or modules, of quarry rock and concrete.
It's an early step in the reef builders' next phase: expanding it from the 22 acres it now covers to the full 150 acres.
They'll do it by filling in the empty spaces between existing modules with more rock. Edison tried squares of both concrete and quarry rock on the 22-acre reef, a kind of pilot project that tested whether one was more effective than the other as attachment sites for kelp.
They ended up performing about the same, Tennant said, but Edison will use only quarry rock for the reef expansion; finding clean used concrete can be difficult.
The scientists are checking the bottom to make sure they don't wipe out any existing habitat in their effort to create a new one.
Even scientists refer to giant kelp informally as a plant, but it's really a form of algae. And finding a healthy understory of other forms of algae along with their attendant marine life might have been a problem, Schroeter said.
"That's the marker of a productive habitat that's been there a long time," Schroeter said. "You don't want to put rocks on top of that."
Luckily, the scientists found no significant understory where they intend to place the rock.
The project began as a mandate from the state Coastal Commission in 1996. The commission was worried that Edison's San Onofre nuclear plant, which began operating in 1983, was harming the marine environment.
The concern was not radiation or nuclear material – nothing above naturally occurring background levels has been released from San Onofre since operations began – but the effects of the plant's cooling system, which sucks in seawater and pipes it back out again a few degrees warmer.
Edison placed screens to keep most fish and other organisms out of the seawater intake pipe, and even installed a kind of elevator that conveys the unfortunate few pulled into the system back out to sea.
But sand kicked up by water flowing in and out of the plant was still a problem. It can bury the rocks that giant kelp needs to anchor itself to the bottom.
The most recent estimate suggests that the plant might have wiped out as much as 178 acres worth of attachment sites for kelp.
Edison officials began the project a bit resentfully and fought the commission, arguing that the potential for damage had been overstated.
But time has brought a transformation. Instead of resenting the effort and expense of the state-imposed project, now approaching $100 million when all the costs are factored in, the company began to take pride in its reef.
Especially when the kelp is robust and healthy, visible from the shoreline and even from satellites in orbit, the expanse of kelp reef became a remarkable success story that gained the company plaudits and public attention.
If all goes according to schedule, quarry rock from Santa Catalina Island will begin to be dumped off barges onto the ocean floor off San Clemente as early as next year.
Soon after, young kelp should cover the rock surface.
Then Tennant will take a boat ride to a thriving kelp forest, home to lobsters, snails, rockfish, surf perch, kelp bass, sea bass and other life forms.
"There were people who said you couldn't grow kelp on artificial substrates," Tennant said. "We found out you can."
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