By Joceyln Kaiser,
Science, January 28, 2000
The U.S. government has given the nod to what could become one of the most ambitious ecological restoration projects ever attempted: rescuing the Salton Sea, a giant lake in Southern California that has become a deathtrap for wildlife. On 13 January; the Interior Department released a blueprint for healing the lake, now on a fast track to looking as lifeless as the Dead Sea. But Congress must come up with $1 billion or more to pay for a full-scale restoration.
Created 95 years ago when engineers accidentally diverted the Colorado River into a desert trough, the Salton Sea once thrived as a resort. But years of agricultural drainage made the 984-square-kilometer lake ever saltier and loaded it with nutrients that spur oxygen-depleting algal blooms. Nowadays it's the scene of fish kills and bird die-offs. Despite its woes, many biologists say, the Salton provides critical habitat for birds moving along the Pacific Flyway, a major migratory pathway, as well as for endangered species such as the brown pelican. The lake's boosters succeeded in convincing Congress to pass a 1998 law that directs Interior to consider solutions for freshening the water, now 25% saltier than seawater, and improving it as a habitat (Science, 2 April 1999, p.28).
Congress also landed $5 million in studies to reconnoiter the lake's chemistry and biology. The just-released results have "dispelled a lot of perceptions" about the sea's health, says wildlife disease biologist Milton Friend, chair of the multiagency Salton Sea Science Subcommittee. "For the first time, we have some good, solid information" that eases concerns that the lake is too polluted to bother saving. Absolved as suspects in the die-offs are pesticides and the element selenium (concentrations of both are too low), and algal toxins, which so far in lab tests do not appear to harm vertebrates. However, many fish are covered with parasitic worms, reflecting unhealthy conditions that might make them more susceptible to other pathogens. Its penchant for poisoning its inhabitants aside, the lake teems with a remarkable array of life-forms. Scientists have counted over 300 organisms not previously reported there, including many microbes new to science. Their studies will appear later this year in Hydmbiologia.
Having concluded that the Salton Sea is worth salvaging as a resource for wildlife, recreation, and agriculture, Interior officials endorse building an evaporation plant and ponds to remove salts, and they have suggested schemes for pumping in fresher water or moving salty water out. Their plan also calls for a permanent science office that would fund studies and work with management on solutions. Congress will need to appropriate money for these projects, which Interior officials admit could cost $1 billion or more over the next 30 years.
Rest stop, in need of restoration. Interior has released a blueprint for saving California's Salton Sea, a mecca for migrating birds.
In the meantime, Salton managers have $8.5 million in hand to move ahead with a pilot project an evaporation tower that will spray a fine mist of lake water into a holding pond, where salt will precipitate. They're also seeking to pay a commercial trawler to harvest fish, which by removing the nutrients sequestered in the fish's bodies would lead to a healthier ecosystem, and they've hired a wildlife biologist whose job is to anticipate and take preemptive measures to alleviate disease outbreaks.
Some critics say the plan doesn't go far enough to tackle tough issues such as stemming the flow of nutrients into the lake. "Birds and fish are going to continue to die unless they address these other problems," says Michael Cohen of the Pacific Institute, a think tank in Oakland, California. The plan does leave many issues unresolved, says Stuart Hurlbert, a limnologist at San Diego State University and staunch restoration advocate, but undertaking a pilot project First, he says, "seems a reasonable way to go?"