Certain amounts of greenhouse gases can be a good thing, as they make the Earth's surface a viable environment for humans and animals. Nonetheless, the over-abundance of these gases, caused largely by the burning of fossil fuels, causes imbalances that are very problematic for our planet. Since the dawn of the industrial age, the world has seen more extreme weather conditions, the loss of complex ecosystems and species, and potential threats to human health due to the planet's changing temperatures.
These disruptive changes can be seen everywhere. Perhaps most noticeably on the icy continent of Antarctica. Recent climate-related changes to Antarctica's landscape has raised eyebrows in the scientific community. The appearance of snow algae is turning the snow green and is becoming increasingly widespread. These green algae could possibly affect the entire ecosystem of Antarctica.
To understand why "green snow" may not be a good sign, you need to familiarize yourself with some of Antarctica's climate and geography. Over the past five decades, the average temperature in Antarctica is thought to have risen by around 5.4 degrees Fahrenheit (3 degrees Celsius). Initially, this might not sound like a very dramatic change but is approximately 5x the mean global warming rate across the planet. Antarctic Peninsula is the most dramatically impacted part of the continent.
Resembling the tail of a horseshoe crab, the Penninsula consists of an 800-mile (1300 km) string of mountains and volcanoes which makes up the northernmost part of the mainland of Antarctica.
This stretch of land is considered to be one of the most rapidly warming places on the continent, and in the world, making it a testbed for scientists studying climate change. In fact, just this year, scientists recorded one of the warmest days on record on the Peninsula, topping out at 20.75 degrees Celsius, or about 69.35 Fahrenheit. A beautiful warm spring day for most people, but fiery hot for Antarctica. So, what are the effects of this warming trend?
Across Antarctica, you can see the impact of rising temperatures on the ice. The Ronne Flichner ice shelf, an area roughly the size of Spain, is now melting at an accelerated rate. In fact, since the 1950s, the continent has lost about 25,000 km2 (9652 square mile) of ice shelf. Melting ice from Antarctica is causing the sea level to rise, and the change in salinity from this influx of freshwater is affecting marine life and the animals (like penguins) that rely on the continent's ecosystem. Green snow algae are but one product of these warmer temperatures.
This is making some areas of Antarctica much greener.
Source: University of Cambridge
In an study recently published in Nature Communications, researchers from the University of Cambridge and the British Antarctic Survey combined satellite data with on-the-ground observations over two summers in Antarctica to detect and measure the amounts of green, snow algae, largely made up of phaeocystis, a single-celled algae well-known in polar areas.
Though individually microscopic in size, these algae blooms have reached such a size that they now color large areas of the Antarctic Peninsula along the western coast, as well as neighboring islands. This snow algae also has another, more colorful name, "watermelon snow, " because of its tendency to simultaneously produce pink or red shades, as this species sometimes also produces a red pigment. However, it is essential to note that researchers focused primarily on green algae for this study.
The University of Cambridge study aims to understand the green snow and how climate change is shaping life in Antarctica. Lead researcher on the study, Dr. Matt Davey of the University of Cambridge's Department of Plant Sciences, shared this sentiment stating, "This is a significant advance in our understanding of land-based life on Antarctica."
"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. Put into context, this is the same amount of carbon emitted by about 875,000 average gasoline car journeys in the UK."
However, the Sentinel-2 system only picks up green algae and misses their red and orange counterparts because the spectral bands of the satellite camera detectors are not sensitive against the associated wavelengths for those particular blooms.
Currently, his team's research is the first large-scale map of microscopic algae blooms along the coast of the Antarctic Peninsula. To properly measure the blooms, researchers combined satellite data with on-the-ground observations over two summers in Antarctica.
Contrary to what you might believe, Antarctica is teeming with wildlife, both on land and the surrounding waters. In fact, there are an estimated 46 species of birds on the continent, which include Albatrosses, Shearwaters and Petrels, Storm-Petrels, Diving petrels, Cormorants, Bitterns, Herons, Egrets, Ducks, Terns, and, of course, penguins, just to name a few.
These bird species flourish on the Peninsula during their short breeding seasons. These birds, however, may also be contributing to the green algae blooms.
Researchers suspect that the "poop" of the local wildlife is serving as fertilizer for the algae. A majority of all blooms occurred within 120 feet of the sea, while two-thirds were within 5 km of a penguin colony. The remaining blooms all seemed to be near other nesting sites.
As mentioned above, the team used images from the European Space Agency's Sentinel 2 satellite taken between 2017 and 2019, combining these measurements with observations from the ground at Ryder Bay, Adelaide Island, and the Fildes Peninsula, King George Island.
For the uninitiated, algae are a diverse group of aquatic organisms that have the ability to conduct photosynthesis, but lack stems, roots, or leaves. You are probably very familiar with some examples of algae, like seaweeds, algal blooms in lakes, or colloquially, pond scum.
There are actually thousands of species of algae in the world. Please note that the algae found in Antarctica are not the same as those found in freshwater.
Algae are the base of the ocean food chain. They take in and eliminate the greenhouse gas carbon dioxide through photosynthesis.
Algae blooms like the ones seen in Antarctica are usually triggered when a combination of sunlight and nutrients create fertile conditions. In the Southern Ocean, iron is the limiting nutrient. When iron concentrations are high enough, algae blooms tend to follow.
As global temperatures increase, researchers are expecting to see more algae blooms in the Peninsula. Lead author of a recent paper, and a researcher at the University of Cambridge and NERC Field Spectroscopy Facility, Edinburgh, Dr. Andrew Grayhas stated, "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."
This may be good news, as more algae mean more carbon sequestration. However, many of the algal fields on low-lying islands could disappear if the snow under them melts completely. At the same time, warmer weather may create new algae fields on the mainland, further to the south and at higher elevations.
The changes to the continent are sure to continue to accelerate over the next couple of decades, and we are yet to fully understand how it will impact the environment locally, and across the planet.
What do you think about Antarctica's "green" change? And, how do you think it will impact the ecosystem of the continent? Leave your answers below.
