Wanted: Algae of the most adventurous type. Must grow in slime on scratchy plastic discs. A willingness to be periodically purged in favor of new recruits required. Above all, must have a hearty appetite for carbon dioxide and a tolerance for scalding temperatures.
This is roughly the job description Keith Cooksey, professor of microbiology at Montana State University-Bozeman, carries with him as searches the hot springs of Yellowstone National Park this winter.
Cooksey’s on a mission, of sorts. Well, a subcontract, really. He’s part of a three-member team looking for ways of naturally lowering carbon dioxide emissions from coal-fired power plants.
Besides Cooksey, the threesome includes David Bayless, a mechanical engineer at Ohio University, and researchers from Oak Ridge National Laboratory in Tennessee. Helping Cooksey at MSU is postdoctoral researcher Igor Brown.
Together, the group has $1-million from the U.S. Dept. of Energy. Cooksey and Brown’s portion of the project is about $100,000 a year for three years. Brown also has support from the MSU Thermal Biology Institute, which similarly studies unique microbes from Yellowstone.
While the coal-fueled power industry has reduced particulate and sulfur emissions, it still produces high amounts of carbon dioxide and other greenhouse gases, now believed to be undesirably warming the planet.
Ohio University is experimenting with ways of absorbing carbon dioxide with algae. Like other plants, algae use the gas as part of their metabolic process called photosynthesis.
Ohio University has piloted Bayless’s technology using algae from the desert. But they believe there’s a better organism out there, and now it’s Cooksey’s job to look.
"If you want thermotolerant, we’re in a good place to look," Cooksey says, referring to Yellowstone National Park. The park is well known for heat-loving organisms that live in and around park hot springs.
"They must be thermotolerant because the gases from these coal-fired power plants–which are about 14 percent carbon dioxide–are hot," Cooksey said. "The gases have been through the scrubbers to get rid of the ash, but they still have lots of CO2."
Is it likely he’ll find what he’s looking for?
"I’m sure it is," he said without hesitation.
"I suspect Keith is right," echoed Ann Deutch, research permit coordinator for Yellowstone Park. "I have no reason to believe he won’t succeed."
After all, fewer than one percent of the park’s microorganisms have been discovered and characterized, Deutch said, meaning so many more algae and related organisms are yet to be found. As microbiologists continue to improve their ability to look, they find greater layers of complexity in the microbial community, she said.
When Cooksey finds some likely candidates, he’ll isolate them and describe them scientifically. The plan is to grow them on plastic sanding discs in a layer of slime called biofilm. Oak Ridge National Labs has figured out how to pipe sunlight to the algae from roof-top solar collectors. Power-plant gases would first be scrubbed of their flyash and sulfur, then piped through mats of algae before going out the smokestack, Cooksey said.
"That exhaust is what we’re going to remove the CO2 from," he said. "We don’t know how much CO2 we can get out of it."
Cooksey also doesn’t yet know how long the algae can do their job before having to be regrown. Harvested algae would likely be used as fertilizer, since they would be rich in both carbon and nitrogen.
Elsewhere, scientists are contemplating other ways of absorbing excess carbon dioxide. One approach, which Cooksey finds troubling, is injecting it into oceans. He’d rather hire a microbe from Yellowstone, born and breed to handle heat, for the hot-gas industrial assignment.
Deutch, too, likes the idea of a Yellowstone microbe finding work as a CO2 scrubber. Sure, it would mean royalties for the park, but turning philosophical for a moment, she said it’s projects like Cooksey’s that make her glad Yellowstone National Park was set aside for future generations.
"When the park was created in 1872, they certainly weren’t thinking of a CO2 scrubber for a coal-fired power plant," Deutch said. "Who’d have known?"