SOURCE: National Science Foundation

DATE: April 10, 2017

SNIP: Microbes in streams flowing on the surface of glaciers in the Arctic and Antarctic may represent a previously underestimated source of organic material and be part of an as yet undiscovered “dynamic local carbon cycle,” according to a new paper published by researchers supported by the National Science Foundation (NSF).

The cycle, they argue, could become a significant global source of carbon as temperatures rise worldwide and microbial activity increases.

Previously, scientists thought carbon released into polar streams by glaciers came from ancient organic material locked in the ice, or from newer sources, such as dust and soot blown in from fires and other sources around the world and deposited on the ice surface. Ice melt then releases that carbon into streams, which flow into the sea.

In the new study, researchers on a glacier in the Antarctic examined the ecosystem of a “supraglacial” stream — one that flows over its surface. Though these streams are among the largest ecosystems on most of the world’s glaciers, models of glacial contribution to the global carbon cycle have not previously considered their potential impact.

The researchers found that most of the carbon in the stream was produced by bacteria photosynthesizing — producing food from sunlight — rather than ancient carbon.

Although this is an initial study of the phenomenon, the research could indicate that as global temperatures rise, particularly in polar ecosystems, which are more sensitive to high temperatures, the microbial output of carbon could increase.