"These algae are such a dominant member of the microbiology community that they can't escape notice, but for some reason they have not attracted much attention," McDermott said.
The Cyanidioschyzon algae grow all over Yellowstone, but the researchers concentrated on the Norris Geyser Basin, McDermott said. The alga thrives in water up to 135 degrees Fahrenheit (too hot to shower) with a very acidic pH factor ranging from 0.5 to 3.5. Creeks are considered acidic if their pH factor is less than 7.
"These algae live in areas of Yellowstone that are extremely toxic with respect to arsenic," McDermott said. "You couldn't drink these waters even if you changed their pH."
The scientists cloned genes from the alga, then studied the enzymes to figure out how they transformed arsenic. They learned that the alga oxidizes, reduces and converts arsenic to several forms that are less toxic than the original.
Rosen said one significant form is a gas that can evaporate, especially at the high temperatures of the Yellowstone springs. That allows life to exist in "really deadly concentrations of arsenic," he said.
"It gives us insight into how life adapts to extreme environments," Rosen added. "If life can grow at high temperatures and high concentrations of heavy metals like arsenic, life might be able to evolve on other planets or moons such as Titan or Enceladus."
McDermott said the scientists conducted basic research that may have implications someday for acid mine drainage and acid rock drainage remediation efforts.
"Any time you learn anything about eukaryotic algae and their potential application for bioremediation, that's always good," he said.
Eukaryotic refers to microorganisms that have cells with membranes enclosing complex structures. Cyanidioschy
|Contact: Evelyn Boswell|
Montana State University