‘Snow algae’ make glaciers less reflective
Microbes living on a glacier can reduce its reflectivity by up to 80 percent, affecting how much sunlight it bounces back into space.
The findings are based on research carried out on the Mittivakkat Glacier in southeast Greenland during summer 2012, which was the hottest summer and fastest-melting season recorded for 150 years.
“Our timing was serendipitous, as it meant we were able to see changes in microbial processes over an extremely fast melting season and observe a process from start to end across all habitats on a glacier surface,” says Stefanie Lutz, a PhD student at the School of Earth and Environment at the University of Leeds.
“This is the most comprehensive study of microbial communities living on a glacier to date,” adds Lutz.
The research, published in the journal FEMS Microbiology Ecology, will help improve climate change models that have previously neglected the role of microbes in darkening the Earth’s surface.
Observing how life thrives at extreme cold temperatures also has important implications for the search for life on distant worlds, such as Jupiter’s icy moon Europa.
“Our three-week field trip revealed a ‘microbial garden’ of life forms flourishing in this cold environment, including snow algae, bacteria, fungi, and even invertebrates,” says Lutz, the study’s lead author.
“Skiers may have seen snow algae before, but not been able to identify it. They are visible to the naked eye as colored snow—most often red—and are frequently referred to as ‘watermelon snow’.”
The reflectivity of a surface is known as its albedo. “Previously, it was assumed that low albedo, which is most often measured from satellites, was primarily due to soot or dust,” explains Liane G. Benning, a Leeds professor and study coauthor.
“However, our research provides a first, ground-based measure for the microbial contribution to albedo. We have shown that albedo is strongly affected by and dependent upon the development and dominance of microbial communities.
“In future climate scenarios, where even more melting is predicted, it is crucial that we are able to better discriminate between all factors affecting albedo.”
The European Union Seventh Framework Programme supported the project.
Source: University of Leeds