Warmer winters accelerate nutrient leaching from alpine grasslands

What is it about?

Mountain regions are facing a dramatic warming. This is especially important in winter, when the shallow soils of alpine meadows are normally frozen and "dormant". We simulated warming by moving plant soil cores from alpine meadows about 300 meters downhill. We found that warmer winters allow nutrient recycling in soils by microbial processes to proceed, releasing large amounts of mineral nitrogen and phosphorus. In spring, plants and microorganisms can use only a portion of the nutrients, and they are increasingly leached into mountain lakes and streams during snowmelt and rainfall, supporting algal and bacterial growth and altering their biodiversity.

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Photo by Joris Beugels on Unsplash

Photo by Joris Beugels on Unsplash

Why is it important?

Alpine meadows are unique and fragile isolated ecosystems, harboring endemic plant species and microorganisms with physiological adaptations to high altitudes. As climate change continues, their character will gradually change due to faster nutrient recycling and longer growing seasons. The processes that occur in their soils have a significant impact on the water quality of glacial lakes and mountain streams, remote waters that are still largely unaffected by direct human activity and that often serve as sources of drinking water. Nutrient leaching from warmer alpine soils promotes the growth of algae and cyanobacteria and, in extreme cases, can lead to algal blooms.