What is this high place ?
Mountains are surrounding you, you can feel the wind from the lack of trees. It looks like the arctic. Let’s wonder a bit further. 

Coming down was a good idea. You can now see clearer, is that a lake that you spot from afar ? Let’s hurry, it’s starting to rain heavily. It is warmer than what you expected here.

+1°c = +7% more moisture in the atmosphere

 The ground doesn’t seem very stable here but it looks quite rich. Browning and greening are happening at the same time.

Looks like you made it to the lake ! Let’s swim ! But the water is so brown… It looks dark, you can’t see what’s underneath, are you sure you want to venture in it ?

You decided to face your fears and jump in!
Welcome to the lake. The water features lots of big algae and plants thanks to the penetrating light, and the fish seem happy here.

The deep wedge in the rocky ground is called permafrost: soil that has been frozen for a long time. Due to multiple factors, some of which you witnessed on your way down—like warmer temperatures, and increased precipitation—permafrost is thawing. When permafrost thaws, the ground becomes unstable and vegetation can collapse. This results in streams of carbon-rich water filled with debris like branches, leaves, and soil, flowing into the lake, while the wind carries other natural debris into the water. Now the water has begun browning, too!

- Let’s dive in, and explore the carbon cycle!
- It has multiple steps that I repeat over and over
- Sedimentation : As I sink into the water, I bring outside carbon with me—like little leaves and sticks that were stuck to my body before I jumped in!
- Burial : I take a little break at the bottom, enjoying the view.
-Decomposition: Then I go back up for air, but usually leave some carbon behind. So I gather some more, and I’m ready for another jump!

The high-latitude lake water is far from empty—it’s home to lots of living organisms. Some are invisible to our eyes, like tiny fish (zooplankton), small algae (phytoplankton), or little remains of birch trees (organic carbon). Some are easily visible, like the larger fish: click on them to learn who they are!
They all coexist in the food web. In browning lakes, populations of organisms that need sunlight to survive, like algae and aquatic plants, are dwindling. This makes it hard for fish to eat, and hide from predators. Like humans, fish can only thrive under certain conditions. (For example, they need sufficient oxygen, safe temperatures, and abundant food.) But just like us, fish have unique tastes and sensibilities. The lake has recently become home to fish species that enjoy nutrient-rich environments, and recently moved in from elsewhere. (Maybe they migrated toward this newly carbon-heavy body of water on their own, or perhaps they were released into the water by humans, for fishing purposes.) Other fish are threatened by their new world—all of a sudden, the lake too warm for them and their eggs to survive, and they struggle to find food in the dark. They might start dying off, or migrating elsewhere, as a result.

Spring to summer

To see how the lake changes, switch between seasons and compare throughout the years. Click on the ice cover for flat charts to appear.
Compare when the ice formed and how long it stayed each year.
Ice forms creating oxygen bubble, the longest it stays the more algies grow on it !

Autumn to winter 

All this data is collected thanks to scientists doing field work to sample the water at any time of the year and through any weather !
Compare when the ice broke and how thick it got each year.
Ice breaks in crystals and almost never get past a meter thick, but it’s enough to hold a truck !