1704734304 Study finds 39watermelon snow has a real impact39 on ice

Study finds 'watermelon snow has a real impact' on ice melt – Radio-Canada.ca

A new study by researchers at Simon Fraser University in British Columbia shows that the phenomenon of “watermelon snow,” also known as “glacial blood,” poses a threat to glaciers, particularly mountain glaciers.

The Rocky Mountains give a colorful appearance in their hostile upper part. This is the phenomenon of watermelon snow, which consists of a thin red-orange layer. It is caused by algae, which gives snow a striking red hue.

The darker the snow, the faster it melts. Researchers highlight the threat snow algae poses to shrinking glaciers in northwestern North America.

Lynne Quarmby, professor of molecular biology and biochemistry at Simon Fraser University, is a snow algae researcher and lead author of a study recently published in Science Advances. She emphasizes that the research results are a warning about climate change.

The loss of algae is just one indicator of the loss of snow and glaciers, which will impact our lives and those of many other organisms.

The study mapped the occurrence of snow algae in the mountains of Alberta, British Columbia and northern Canada, as well as in Alaska, Idaho, Montana and Washington state.

Researchers have developed a machine learning program to analyze more than 6,100 satellite images of glaciers taken between 2019 and 2022.

The study found that red-pigmented algae blooms contribute to melting glaciers. But global warming poses a much greater threat to mountain glaciers and the surprisingly complex microscopic ecosystems in which snow algae can colonize.

A survival mechanism for algae

Supported by a large ecosystem of bacteria and fungi, snow algae thrive when water and nutrients are released by melting snow. This phenomenon is due to the proliferation of Chlamydomonas nivalis, a single-celled species of green algae that thrives in temperatures close to freezing.

Through photosynthesis, flowers act as carbon sinks, absorbing carbon dioxide from the atmosphere.

Snow algae have a red pigment that allows them to survive in harsh mountain environments. “When they bloom, they give the snow this red hue,” explains Lynne Quarmby.

Blooms darken the surface of summer snowfields so that they reflect the sun less, which accelerates the melting of snowpack and ice.

The darker shade also serves as a sunscreen and protects the algae from sun damage.

Quarmby and her colleague Casey Engstrom at Simon Fraser University set out to create a large-scale map of microscopic ecosystems. They found that between 2019 and 2022, more than 4,214 square kilometers of the glacial landscape, or 4.5% of the entire study area, was covered in reddish snow. The impact [des algues] is noticeable, it is real, she said.

A hiker holds a handful of

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Every summer, colorful algae colonize thousands of snowfields in North America.

Photo: Associated Press / Rick Bowmer

Three centimeters of cast iron

Researchers estimate that the colored snow contributed an average of three centimeters of snowmelt per season.

Snow algae were found on 4,552 of the 8,700 glaciers examined. Some only had a spot while others had large flowers. For example, in 2020, algae covered nearly two-thirds of the surface of Alberta's Bow Glacier in the Wapta Icefield.

The glaciers along the Pacific Northwest coast are usually teeming with algae, but during the heat dome three years ago, the ice melted so quickly that the blooms didn't have time to develop.

According to Lynne Quarmby, as the snow begins to disappear as temperatures rise, the algae will also disappear. This means the loss of a valuable ecosystem that scientists are only beginning to understand.

According to Scott Hotaling, an ecologist at Utah State University who was not involved in the study, the results of Lynne Quarmby and Casey Engstrom's research provide an important basis for assessing the impact of snow algae on retreating glaciers.

With information from Wallis Snowdon