"After we diverted the water into the channel, photosynthesis began the same day and the mats became abundant within a week," she said. "This showed us that they had been preserved in a cryptobiotic state."
Over the next several years, the microbial mats in the experimental channel had higher growth rates than mats in adjacent streambeds receiving annual summer water flow, she said. The study showed the new microbial mats were taking up atmospheric nitrogen at a higher rate than mats in adjacent streambeds, increasing biomass productivity, she said. As photosynthetic bacteria, cyanobacteria are believed by biologists to be among the first living organisms to colonize Earth. The mats generally are orange or black and consist of 10 to 15 different species of cyanobacteria, she said.
Because of a cooling trend in the McMurdo Dry Valleys, some streambeds that normally have annual summer flows have been dry in recent years, McKnight said. In contrast, the Antarctic Peninsula has warmed nearly 5 degrees Fahrenheit in the past 60 years and has seen the collapse of several major ice shelves and significant glacial thinning in recent years, according to several international studies.
The McMurdo Dry Valleys region consists of glaciers, open expanses of barren ground, stream channels and permanently ice-covered lakes. The life forms inhabiting the area include microorganisms, mosses, lichens and a few groups of invertebrates.
Study collaborators included Cathy Tate of the U.S. Geological Survey, Denver; Ned Andrews of the USGS, Boulder, Colo.; Dev Niyogi of the University of Missouri-Rolla; CU-Boulder graduate student Karen Cozetto; Cathy Welsh and Berry Lyons of Ohio State University; and Douglas Capone of the University of California, Irvine.
The McMurdo Dry Valleys site is one of 26 LTER sites in the world designated by NSF. Approximately 25 scientists participate in research during each field season.
Source:University of Colorado at Boulder