PACIFIC TIDEPOOLS: A THREATENED ECOSYSTEM?

An astonishing diversity of life dwells in the crystal-clear pools that format low tide along America's Pacific coast. A vast array of invertebrates feed off the hundreds of species of densely growing flora, which range from microscopic diatoms to huge, well-anchored seaweeds. Birds, fish and mammals feast on the barnacles, snails, urchins and other animals that vary from tiny shore crabs to spectacular giant green anemones. But could these tidepools be in danger?

"Intertidal life is the most vulnerable of all marine life," says John Pearse, an emeritus professor of biology at the Institute of Marine Sciences at the University of California, Santa Cruz. "It's where the air, land and sea all come together. They're right on the edge of extremes, so they are the first to feel the effects of temperature changes or pollution."

The once-dominant California mussel has vanished from many areas, the black abalone has been nearly wiped out by collectors and disease, and the ochre sea star, once the most common sea star, is now found only occasionally.

"Possibly the greatest threat to coastal flora and fauna is the impact of non-point source runoff," says Marco Gonzalez, chairman of the Surfrider Foundation of San Diego. "Building roads, especially large highways, near the coast results in additions of toxic pollutants to the near-shore environment. Tide pools are mini-ecosystems that can easily be thrown off balance." Relentless coastal development has also taken its toll on tide pools.

In addition, there are new threats that may pose even greater danger if not kept in check. In Southern California, there is an infestation of Caulerpa taxifolia, a seaweed used in tropical aquariums. "The algae poses an immediate threat to the coastal embayments where it has been found, including California's Agua Hedionda Lagoon and Huntington Harbor," says Chiara Clemente, an environmental specialist with California's Regional Water Quality Control Board. "The biggest fear is that the algae will be found in the open ocean. C. taxifolia infestations have spread along the Mediterranean coast and have dramatically altered and displaced native plant and animal communities. Governments are now unable to control its spread, as more than 3,360 acres are affected."

As long as the waves of the sea continue to flow over the tide pool zones, marine creatures will probably exist there. The question becomes, will the survivors be those that are too tough to destroy, too unappealing to eat or not interesting enough to place in an aquarium? CONTACT: Regional Water Quality Control Board, [phone], www.swrcb.ca.gov; Surfrider Foundation San Diego, [phone], www.surfridersd.org.