Why Is Antarctica Turning Green?

Antarctica makes up just under 10% of the total landmass on planet Earth, the vast majority of which is covered by ice and snow. However, there are signs of life which creep in on the peripheries of the continent, as algae, lichen and moss all grow along its coastal edges – some of which has been there for more than a millennium. With global warming melting Antarctic snow at a faster rate than ever before, those green spots are now covering ever larger areas.

In fact, a new six-year study has demonstrated that algae blooms are turning Antarctica green at an unprecedented rate. This, in turn, is having a deleterious effect on the continent’s ability to reflect heat from the sun and thus exacerbates the warming problem, even while it acts as a carbon sink and provides potentially vital nutrients to other lifeforms living in the vicinity.

Shoots of green

The new research was conducted by a team of scientists from the University of Cambridge and the British Antarctic Survey, who studied the concentrations of algal blooms on the Antarctic Peninsula over a six-year period. Published in the journal Nature, their findings were arrived at by using a mix of satellite imaging data and on-the-ground observations.

The team identified 1,679 distinct patches of algae growth covering an area of the peninsula 1.9 square kilometres in size. Almost two-thirds of the algae were found on low-lying islands near the peninsula, which are particularly susceptible to the immediate consequences of global warming. A similar percentage was found within five miles of penguin colonies, indicating that the nutrients found in the birds’ excrement was a key driver in the algae’s growth.

Good and bad consequences

While these algal blooms are not as dangerous as the blue green algae plaguing ponds, lakes and streams in warmer climes, they do have some harmful effects on their surrounding environment. Chiefly, they adversely impact the snow’s ability to reflect heat from the sun, which has been instrumental in maintaining Antarctic snow and ice for as long as possible. While snow can reflect up to 80% of radiation, the algae-covered areas can only reflect up to 45%.

On the other hand, these new lifeforms do bring some good news with them. For one thing, they act as a carbon sink for CO2 in the immediate vicinity, with the area discovered by the study capable of absorbing around 479 tonnes of carbon each year. That’s equivalent to approximately 875,000 car journeys in Britain, though its global effect is fairly negligible.

More study needed

Another, less well understood consequence of the algae is its effect on other lifeforms. Because it can form symbiotic relationships with bacteria, fungi and spores, the algae could prove a breeding ground for biodiversity. “It’s a community. This could potentially form new habitats,” explained Matt Davey, a scientist involved in the study. “In some places, it would be the beginning of a new ecosystem.”

As is often the case with studies of this kind, its authors stress that more research is required to fully understand the environmental effects of the algae’s spread. In order to figure out whether its overall effect will be beneficial or detrimental, future studies must concentrate on the snow’s albedo quality (ability to reflect heat), while also incorporating other types of algal bloom, such as red and orange ones.