Extreme Diversity—in Soap Lake
by Tina Hilding | © Washington State University
From the strange waters of Soap Lake come unique forms of life
At first glance, Soap Lake doesn't seem to offer much to 21st-century science.
Amidst a largely treeless primeval landscape, the lake is surrounded by stark shores and sheer rock walls.
A few lakeside resorts and cabins dot its shores, where Native inhabitants once came for beneficial mineral baths. The adjacent town of Soap Lake, Washington, located 20 miles north of I-90 near Moses Lake, is one-fourth the size of its earlier heyday, when people came for treatment of a malady similar to gangrene.
But landscape rather than history prevails. Civilization seems a mere blip on the area's timescale. Even the water itself seems never to change. The lake is permanently stratified, so that its two layers have not mixed for at least 2,000 years, the longest documented stratification of any lake on earth.
It's Soap Lake's unchanging nature that attracts researcher Brent Peyton, associate professor of chemical engineering at Washington State University. In a place that time seems to have forgotten, Peyton is working to learn about tiny microorganisms that could be key to solving 21st-century problems in areas from pharmaceuticals to environmental cleanup. The lake may even be of help in the search for extraterrestrial life-forms.
Peyton is examining the tiny bacteria that make their home in Soap Lake, a harsh environment that is toxic to most higher life-forms. The microorganisms are called extremophiles, because they live in highly unpleasant places where few others can live, like the bottoms of oceans, dry desert salt flats, or ice-covered lakes in Antarctica. The water at the bottom of Soap Lake, for example, is five times saltier than ocean water, and contains high, naturally occurring concentrations of carbonate, chloride, sulfate, and sulfide. Because extremophiles spend their lives in such inhospitable places, they have developed unique and potentially useful biological processes. The enzymes they produce, for instance, are tougher and more stable than typical enzymes, and could be used in chemical reactions that take place under harsh conditions.
Peyton spent several years trying to solve environmental problems on the Hanford Nuclear Reservation—in particular, the movement of contaminated groundwater that someday may make its way to the Columbia River. In his research, he used commonly found bacteria to precipitate uranium and other heavy metals out of groundwater and to lock them up as solids in the soil. He was one of four WSU researchers, in fact, to receive a $900,000 grant from the U.S. Department of Energy in a multidisciplinary project to work on the bioremediation of chromium.
Enter Halomonas campisalis
But it wasn't until he began working with chemical companies to figure out a way to use microorganisms to clean up hazardous chemicals from their waste streams that he became interested in extremophiles. Because these streams contain high levels of salt, the companies must dilute them with lots of fresh water before they can begin to clean them up. The process can be expensive, time consuming, and wasteful.
The search for microorganisms that can survive the harsh conditions of high-salt waste streams led Peyton to his research on extremophiles. Searching near Soap Lake, he found Halomonas campisalis, which he named for the salt flats where it makes its home. H. campisalis looks like a cross between cotton candy and a jellyfish when grown in a lab culture, with delicate pink tendrils that reach out in all directions. Living in a salty waste stream, the microorganism eats hazardous chemicals called phenols, converting them to harmless carbon dioxide and water. In an alkaline environment, H. campisalis produces muconic acid, a precursor to nylon, a valuable product in the chemical industry. Both capabilities are something that the chemical industry may be able to use.
"These capabilities can be used where normal organisms would roll over and die,'' Peyton says.
National Science Foundation Grant
Soap Lake's unique organisms have attracted the attention of the National Science Foundation. With an $840,000 NSF grant, Peyton, Holly Pinkart of Central Washington University, and Melanie Mormile of the University of Missouri-Rolla are studying the lake as an NSF microbial observatory, exploring life in its natural extremophile communities. Among the questions the scientists want to answer are how the bacteria have survived at the lake bottom for thousands of years, what types of food they eat, and the rate at which they transform natural carbon compounds. The researchers are isolating new organisms that have never before been characterized. In particular, they are focusing their work on the deep, anaerobic portions of the lake. Peyton hopes that some of these new types of microorganisms could be useful for industrial applications.
"There is a lot of value in just understanding life in these extreme environments,'' he says. "Life is much more diverse than people typically think.''
Some scientists believe, in fact, that life may have begun in a lake similar to Soap Lake, and that the lake could offer clues to where life on other planets might exist. Some believe that Mars, for instance, once had seas that have since dried up. As the seas dried, small pockets of salty water, perhaps similar to Soap Lake, may have remained. Data from Soap Lake will be used to improve satellite-based searches for similar areas on other planets. As part of the project, the researchers are providing data for the Virtual Planet Database being developed by the Jet Propulsion Laboratory at the California Institute of Technology that will be used in the search for extraterrestrial biological systems.
A New Consortium
Representing WSU, Peyton has joined with scientists from the Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL) and Concurrent Technologies Corporation, a nonprofit based in Johnstown, Pennsylvania, to establish the Consortium for Extremophile Research. The group is dedicated to researching and developing new products and processes that use the unique capabilities of these microorganisms.
The researchers are working on several projects, including the use of alkaline-loving bacteria to dispose of industrial wastes; understanding climate change through the study of methane-forming bacteria in the Arctic; and decontaminating radioactive wastes on surfaces.
Peyton is one of a group of researchers who envision using alkaphiles—bacteria that love alkaline environments—to convert agricultural waste to useful products and chemicals. The group is also looking to use microorganisms in the destruction of pesticides, nerve gases, and high explosives. Microorganisms from Soap Lake have successfully degraded the pesticide atrazine, for instance.
The three participating institutions all have significant expertise that makes them valuable partners in the consortium. The WSU researchers are leaders in using haloalkaliphilic microbes as catalysts in chemical reactions for environmental applications. INEEL researchers have demonstrated expertise in extremophile microbiology for a variety of bioenergy, national security, and environmental applications, including removal of radioactive contaminants from surfaces. Concurrent Technologies specializes in getting research transferred and applied in the public and private sectors.
"Putting together this consortium builds something bigger than the sum of our already-strong programs and will bring our research all the way from its start in the laboratory to application in the marketplace," says Peyton.
Running Out of Time?
Peyton actually doesn't often go to Soap Lake to take samples. That's because when he does, he usually comes home with several microorganisms that nobody has ever seen before. Instead, he spends most of his time learning about the metabolic reactions and properties of the microorganisms he's found.
He compares the desolate Soap Lake to the heart of the rain forest. Like the rain forest, the lake is home to many organisms with unique capabilities, perhaps some with the potential to solve pressing human problems. And, like the rain forest, this unique environment is constantly under threat, ranging from possible dilution by irrigation projects to pollutant runoff from a variety of human activities, endangering valuable organisms that aren't even known yet.
As Peyton sends his collecting equipment to the bottom of this seemingly timeless lake, time, in fact, may be running out.
Tina Hilding is communications coordinator for the College of Engineering and Architecture.
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