Everyone knows Antarctica is a beautiful white desert. Snow. Cold. Ice. Penguins. That’s what springs to mind when someone mentions Earth’s southernmost continent. But climate change is warming our planet, and Antarctica is not being spared. Scientists have spotted green snow on Antarctica, and it’s not good news. There’s so much green snow on Antarctica right now; it’s visible from space.
The algae that grow on the white continent are spreading at a faster pace as our planet warms up. Although the presence of algae in Antarctica was predicted a long time ago by various expeditions, such as the one carried out by the British Ernest Shackleton, its full extent was unknown.
Now, a team of scientists has made the first large-scale map of microscopic algae off the coast of the Antarctic Peninsula and has warned that plant life will continue to spread across the icy continent as global temperatures rise due to climate change. That’s a fact for everyone who still thinks “climate change” isn’t a thing.
Although each algae is microscopic, when they grow en masse, they make the snow turn bright green, a phenomenon that can be seen from space and is called “green snow.”
The scientific team, with researchers from the University of Cambridge and the British Antarctic Survey, has combined satellite data and field observations from two summers to understand the extent of the problem at Antarctica.
It’s not good news. The results of the study represent a “significant advance in our understanding of terrestrial life in Antarctica and how it could change in the coming years as the climate warms up,” explains Matt Davey, from the Department of Plant Sciences at the University of Cambridge and director of research.
“Snow algae are a key component of the continent’s ability to capture carbon dioxide from the atmosphere through photosynthesis,” revealed Davey.
These green algae blooms are found around the Antarctic coast, particularly on islands along the western coast of the Antarctic Peninsula, which are essentially much warmer areas where the average temperature is just above zero degrees Celsius in the southern summer, which in the southern hemisphere runs from November to February.
The Antarctic peninsula experienced the fastest warming in the latter part of the last century.
The study finds that the distribution of green algae in the snow is also “strongly influenced by birds and marine mammals,” whose “poop” acts as a highly nutritious natural fertilizer that accelerates the growth of algae. In fact, more than 60% of the algae is less than five kilometers from a penguin colony, and close to places for bird nesting or seal landing.
Penguins poop, algae grow. This, of course in correlation with clear changes in Earth’s climate.
For the recent study, scientists used images from the European Space Agency’s Sentinel 2 satellite that were taken between 2017 and 2019 and combined them with measurements made in Ryder Bay on Adelaide Island and on the Fildes Peninsula on King George Island.
“We identified 1679 separate blooms of green algae on the snow surface, which together covered an area of 1.9 km2, equating to a carbon sink of around 479 tonnes per year” said Davey.
Nearly two-thirds of the green algae blooms were on small, low-lying islands without high ground.
As the Antarctic Peninsula warms due to rising global temperatures, these islands may lose their summer snow cover and, with it, their snowy algae. However, in terms of mass, most of the snow algae are found in a small number of larger clusters in the north of the Peninsula and the South Shetland Islands, in areas where they can spread to higher lands as the low snow melts.
“As Antarctica warms, we predict the overall mass of snow algae will increase, as the spread to higher ground will significantly outweigh the loss of small island patches of algae,” said Dr Andrew Gray, lead author of the paper, and a researcher at the University of Cambridge and NERC Field Spectroscopy Facility, University of Edinburgh.
Antarctica is the southernmost continent in the world, typically known as a frozen land of snow and ice. But terrestrial life can be abundant, particularly along its coast, and is responding rapidly to climate change in the region. Mosses and lichens form the two largest visible groups of photosynthetic organisms and have been the most studied to date.