Climate change leading to an increase of green snow in Antarctica

Cheryl Sanders
May 22, 2020

Credit: Wikimedia Commons. "With the available area for plant colonization on the Peninsula likely to increase by up to threefold due to this warming, understanding how snow algae fit into Antarctica's biosphere and their probable response to warming is critical to understanding the overall impact of climate change on Antarctica's vegetation", the study reads. Researchers say a larger area of the Antarctic coast will be covered by the algal blooms as global temperatures increase.

In some areas, these single-cell life-forms are so dense, they turn the snow bright green. these can also be spotted from the space, according to the study.

Their work found 1,679 blooms of algae, covering a total area of 1.9 square kilometres, equalling carbon sink - or a natural environment's ability to absorb carbon dioxide from the atmosphere - of about 479 tonnes a year.

Researchers found that nearly two-thirds of the blooms were on small, low lying islands, and said that as the Antarctic Peninsula warms due to rising global temperatures, these islands could lose their summer snow cover and algae - although in terms of mass the majority of snow algae is found in areas where they can spread to higher ground when snow melts.

Gray told AFP that the green snow blooms on higher ground would "more than offset" the effect of sea-level algae losses.

Dr Matt Davey in the University of Cambridge's Department of Plant Sciences, who led the study, said the algae could capture carbon dioxide, which could be a boost in the battle against climate change. Put into context this is the same amount of carbon emitted by about 875,000 average petrol vehicle journeys in the UK.

They found most of the blooms were on small, low-lying islands that are expected to lose their summer snow under warmer global temperatures.

However, while an increase in snowmelt could lead to more algae growing, Gray told CNN that the distribution of the organisms is heavily linked to bird populations, whose excrement acts as a fertilizer to accelerate growth. They bloom when the temperature is warmer than normal, between November and February, the austral summer. They plan further work to measure these other algal blooms, and also to measure the blooms across the whole of Antarctica using a mixture of field work and satellite images.

Above: Multi-coloured snow algae on Anchorage Island, in Antarctica. But terrestrial life can be abundant, particularly along its coastline, and is responding rapidly to climate changes in the region. "It's the beginning of a new ecosystem".

While the presence of algae in Antarctica was noted by long-ago expeditions, such as the one undertaken by British explorer Ernest Shackleton, its full extent was unknown.

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