Humans Have Influenced the Growth of Blue-Green Algae in Lakes for Thousands of Years

Typography

In recent years, there have been increasing reports of toxic blue-green algae blooms in summer, even in German lakes, caused by climate warming and increased nutrient inputs.

In recent years, there have been increasing reports of toxic blue-green algae blooms in summer, even in German lakes, caused by climate warming and increased nutrient inputs. But humans have not only had an influence on the development of blue-green algae since modern times, but already since the Bronze Age from about 2,000 B.C. This is the result of a study by researchers from the German Research Centre for Geosciences GFZ and colleagues, published in the scientific journal “Communications Biology”. Since some blue-green algae, also known as cyanobacteria, leave no visible fossil traces in sediments due to their small size, little is known about how they evolved in our lakes during the last centuries and millennia. Using DNA from sediments, the researchers have now been able to decipher for the first time the history of blue-green algae over the last 11,000 years in the sediments of a lake in Mecklenburg.

Blue-green algae have proliferated in many bodies of water in recent decades. The causes are man-made: increasing nutrient inputs and global warming. Some blue-green algae species are toxic, so that mass blooms in bathing waters can even be hazardous to health. They can cause allergies if they come into contact with the skin or – in the case of small wounds – infections and – if they get into drinking water, for example – can even cause liver cancer in extreme cases.

Read more at: GFZ Geoforschungszentrum Potsdam, Helmholtz Centre

TERENO Monitoring Station on Lake Tiefer See, Germany (weather station, water probes, sediment traps). (Photo Credit: A. Brauer)