Tim McDermott at Lemonade Creek in Yellowstone National Park. The hot spring fed-creek is green because the arsenic-eating algae have formed a thick mat. (Credit: Photo courtesy of Tim McDermott)
Arsenic may be tough, but scientists have found a Yellowstone National Park alga that’s tougher.
The alga — a simple one-celled algae called Cyanidioschyzon — thrives in extremely toxic conditions and chemically modifies arsenic that occurs naturally around hot springs, said Tim McDermott, professor in the Department of Land Resources and Environmental Sciences at Montana State University.
Cyanidioschyzon could someday help reclaim arsenic-laden mine waste and aid in everything from space exploration to creating safer foods and herbicides, the scientists said.
The alga and how it detoxifies arsenic are described in a paper that’s posted this week (week of March 9) in the online edition of Proceedings of the National Academy of Sciences, or PNAS. Lead authors are McDermott and Barry Rosen, of Florida International University. Among the four co-authors is Corinne Lehr, who formerly worked with McDermott as a postdoctoral scientist at MSU and is now a faculty member at California Polytechnic State University.
Arsenic is the most common toxic substance in the environment, ranking first on the Superfund list of hazardous substances, the researchers wrote in their paper. McDermott said arsenic is very common in the hot, acidic waters of Yellowstone and presents real challenges for microorganisms living in these conditions. Indeed, there are challenges for the researchers. McDermott said the acid in the soil and water are strong enough that it sometimes eats holes through his jeans when he kneels to collect samples.
McDermott has worked in Yellowstone for more than a decade and travels year-round to the Norris Geyser Basin to study the microbial mats that grow in acidic springs. Over the years, he noticed thick algae mats that were so lush and green in December that they looked like Astro-Turf, McDermott said. By June, they were practically gone. While investigating the change, McDermott and his collaborators learned about the Cyanidiales alga and its ability to reduce arsenic to a less dangerous form.