Sweden’s surface is 9% lake, which shows how important lakes are to the country’s environment.
The Arctic, known for its negative temperatures most of the year, hosts quite a few of Sweden’s lakes. Scientists have been studying them closely since 1913, allowing us to see what’s been happening to these precious ecosystems over the past hundred-plus years.

Here is what a typical high-latitude lake looks like.
- The vegetation, composed of birch and wild grass, is slowly moving north (this, again, is called “Arctic greening”) but collapses frequently, too (also known as “browning”).

- The area is quite rocky, as the lake sits on a bed of rocks.

- Organic matter is transported into the lakes by runoff from higher lakes, precipitation, thawed permafrost, and wind.

Summer to autumn
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 bubbles. The longer it sticks around, the more algae will grow on it!

Winter to spring
All of this data is collected thanks to scientists’ fieldwork, as they sample the water at all points of the year and in any weather!

Compare when the ice broke, and how thick it got each year. Ice breaks in crystals and almost never gets past a meter thick, but it’s enough to hold a truck!