Shifting Seasons on the Steppe

Shifting Seasons on the Steppe
Shifting Seasons on the Steppe

From above, the linear features in the Kulunda steppe of southwestern Russia looks as if a large claw has scraped the land surface. In reality, the features are a byproduct of tectonic forces that folded rock layers in ways that created shallow, boggy valleys that are now filled with pine forests and lakes.

The expansive grasslands surrounding the valleys has a long history of being one of Russia’s most important breadbaskets. Intensive production and overuse during the Soviet era led to significant erosion of the soil in many places, but farmers in the area still manage to grow a range of crops, including wheat, sunflowers, buckwheat, soybeans, flax, peas, and sugar beets.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites acquired this pair of images on April 1 and June 11, 2020. The forested valleys appear dark green in comparison to the lighter green and brown farmland that surrounds them. The loss of snow and ice cover is the most obvious seasonal change in the image pair, but notice also how the color of Lake Kuchukskoye shifts from green to pink.

Many of the salt lakes in Russia’s Alta Krai district undergo a seasonal color change as populations of aquatic organisms such as salt-loving Halobacteria and brine shrimp increase in the summer. Many of the lakes achieve their most intense flamingo-shades of pink in July and August, when the water becomes especially salty due to hot, dry weather, which increases the rate of evaporation and lowers lake water levels.

In recent years, Kuchukskoye’s water has usually turned pink by the last week of June or the first few weeks of July. This year, the color change happened earlier than usual—in the third week of May—likely because Siberia experienced an unusually intense and prolonged heat wave.

NASA Earth Observatory images by Lauren Dauphin, using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview. Caption by Adam Voiland.

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