"Browning" Lakes Look Like Alien Landscape in Climate Change Study
Gone are the days when we could count on the Arctic landscape to be painted in shades of white. The permafrost beneath the snow and ice is no longer permanently frosty, and as it melts, write researchers in a new study, it’s muddying up the once-pristine terrain — quite literally. In a startling photo accompanying the study, an array of Arctic and sub-Arctic lakes seem to spew filth from within, making the landscape look like the surface of an alien world.
The paper, published in Limnology and Oceanography Letters on Friday, describes the visible effects the thawing permafrost has on the surface of the neighboring terrain, many feet above it. As climate change warms the Earth and coaxes the permafrost out of its continually frozen state, a process called “browning” occurs, the researchers write. During this process, organic carbon once trapped deep in the permafrost seeps upward into the region’s lakes and ponds, suffusing them with a filthy brown hue. Meanwhile, the way the permafrost cracks the landscape above it creates fissures that divide the surface into eerie polygonal shapes.
In the image below, supplied in a release by Quebec, Canada’s INRS (*Institut national de la recherche scientifique), the muddiness of the browning lakes sharply contrasts with the clear blue of the larger body of water alongside them, though even it too shows sinister brown tendrils curling up along its edges.
Here’s an aerial photo of Bylot Island, which lies off the northern side of Baffin Island in the Nunavut territory of Canada, southwest of Greenland:
Browning doesn’t just make the collection of lakes look like the sickly cells of an alien organism’s skin. The biggest downside of all that organic carbon seeping to the surface, INRS biologist Isabelle Laurion, Ph.D. and her co-authors write, is that this carbon is really good at absorbing sunlight, which drives up the temperature — and thus the rate of permafrost melt — even faster.
Laurion and colleagues determined this by analyzing the different types of dissolved organic matter in 253 ponds around the North Pole, which showed them that the waters affected by thawing permafrost contained much more terrestrial carbon and less algae (a key element to the food chain in these waters).
“Our results demonstrate a strong terrestrial imprint on freshwater ecosystems in degrading ice-rich permafrost catchments, and the likely shift toward increasing dominance of land-derived organic carbon in waters with ongoing permafrost thaw,” they write.
In a paper published in Scientific Reports in 2015, researchers outlined the ecological effects of browning. In the lake they studied, over the course of 27 years, surface water temperatures increased by 2–3 degrees Celcius, the lakes became five times more transparent to UV light, and levels of zooplankton (near the bottom of the food chain) decreased.
But perhaps the worst effect of browning is that it creates conditions even more conducive to releasing even more carbon into the air — particularly in the form of the greenhouse gas methane — which will in turn speed up the climate change process by which the permafrost melts in the first place.
“Land-derived organic carbon is having a growing influence on Arctic and subarctic ponds, which carries over into the food web,” the authors said in a statement. “The browning of these systems leads to oxygen depletion and cooler water at the bottom of the ponds, which can have a major impact on the microbial activity responsible for the production and consumption of greenhouse gases, particularly the production of methane, a powerful greenhouse gas.”