A Quick Peek at Antrarctic Lifeforms
When most people think of Antarctica, they probably think of one of a few things: penguins; snow and cold climates; or the South Pole. Not everyone realizes that Antarctica is actually the world’s largest desert, with an area equalling the Sahara, Australian, and Arabian Deserts combined. In fact, it is home to some of the driest places on the planet. In addition to the cold and harsh environment, there’s little that wants to live there. That doesn’t stop life from looking to flourish on our coldest continent.
Antarctica, on average, gets about 166 millimeters of precipitation a year, most of which comes in the form of snow. The amount of precipitation in an area can vary wildly though. The wettest places, like the Antarctic Peninsula, can get up to 635 millimeters, while others get a mere 50 millimeters, such as in the interior where the elevation is high. The interior is also extremely cold, ranging from a frigid -90 degrees Celsius to just below freezing. On the peninsula, it can occasionally reach almost 20 degrees Celsius in the summer, but often stays closer to 0 degrees Celsius. The weather across the entire continent can be unpredictable, changing at the drop of a hat.
In short, Antarctica is near uninhabitable except to enterprising scientists and the toughest of fauna and flora.
Life in Antarctica is different. We don’t see the tall trees or large plants that we see in much of the world. The absence of most insects makes it the only continent without ants. The life that does exist in Antarctica, though, gives us insight into what conditions are actually needed for life to exist. Some of the living conditions in which microbes are found let us speculate what life outside of our planet might be like.
One of the largest groups of flora is lichens, of which 250 different species live in Antarctica. They grow on rock outcroppings, bright oranges and muted yellows covering entire areas, peeking through where the snow has melted. The rocks don’t have to just be coastal, some have been found within even just a few hundred kilometers of the South Pole. Lichens grow in the volcanic regions and in the McMurdo Dry Valleys. They’ve adapted to life in the antarctic, having developed the ability to photosynthesize while frozen. They can pull water from the air or snow, but also survive long droughts by becoming inactive. Even being snow-covered isn’t enough to get them down, as it seems most of their growth happens when the lichens are protected from the harsh environment by snow.
Where the snow doesn’t melt, algal blooms can take hold, coloring snow banks in greens and reds. These different colors are actually signs of the algae’s life cycle. A swath of green shows the algae spreading and finding its home. The lengths of red or orange are spores that are settled and waiting out the harsh temperatures that the green algae can’t survive. The snow algae grows mostly in the coastal snows during the summer.
The Antarctic Peninsula has the largest visible biodiversity on the continent. The fact that it’s the northernmost and wettest part lends itself well to the variety of life. The Antarctic Pearlwort is a short plant that grows in mounds in between rocks. It has a moss-like appearance but grows little, yellow flowers. The Antarctic Hair Grass is the other flowering plant calling the Antarctic Peninsula home. As a grass, its flowers aren’t always noticeable, but it grows much like the pearlwort. Small tufts of green grass poke through spaces on a rocky landscape. A perennial plant, it lives for a couple years before turning yellow as it ages out.
The peninsula is also home to a variety of animal life. Most of the animals found here are birds and marine life, but that’s not all that lives there. The largest purely terrestrial animal in Antarctica is Belgica antarctica, a flightless midge. It grows to be only 6 millimeters long and can survive temperatures as low as -15 degrees Celsius. While Antarctica does get colder than that, the midge knows to crawl under the snow, where the temperature sticks close to 0 degrees Celsius year round, to avoid freezing in the winter. It has also adapted to only survive in these cold temperatures. The midge’s larvae don’t survive warm temperatures - even 10 degrees Celsius is too warm.
As with much of the world, most of the life to be found in Antarctica is microscopic. In some places, it’s the only kind of life to be found. Such is the case with the McMurdo Dry Valleys, which live up to their name. The valleys only get four inches of snow in a season, which quickly evaporates, leaving the ground dry. Glacial runoff provides the majority of the water the area sees in the summer, as it hasn’t rained in the valleys in almost two million years. In addition to the glacial meltwater, it has a few lakes that are covered in ice year round, though they do partially melt at the peak of summer. The Dry Valleys are the driest place on Earth, and often the only macroscopic animals to be found are seals and penguins that have been mummified by the climate.
That doesn’t mean it is completely unlivable in the Dry Valleys. Scottnema lindsayae, a nematode endemic to Antarctica, is often the only nematode to be found in the driest parts of the Dry Valleys. It’s adapted to the cold and dry life, thriving in the higher altitudes and preferring areas with higher concentrations of carbon over areas that are moisture-rich, but carbon-poor.
Bacteria living in the Dry Valleys live in a few different places. Some bacteria are endolithic. They find the moisture in cracks in rocks and live there, staying safe from the dry climate. Anaerobic bacteria, bacteria that don’t need oxygen, live beneath Taylor Glacier, a glacier in the Dry Valleys, in the frozen ground.
The lakes also host cyanobacteria. In Lake Vida, the bacteria live in a brine below twenty meters of ice. The lake has been cut off from the outside world for almost three millenia, from when it first froze and stayed frozen, so the bacteria here give an insight to ancient life. The conditions of the lake have let the bacteria live, though they don’t do much outside of simply existing. Some of the bacteria that had been thawed in a lab started to show more life and even began to reproduce.
This is just a small peek at what lives in Antarctica. It’s a vast continent with many different ecosystems, from frozen lakes to volcanic fumaroles; from rocky mountains to coastal cliffs. Mosses and algae color the landscape; tardigrades and penguins grace the continent. There’s a lot more to discuss when it comes to what lives in the Antarctic, and probably much more to discover still. It’s hard to live there, but many plants, animals, and otherwise have learned to survive in the harsh environment.