Rivers and streams contain DNA belonging to organisms such as fish, vertebrae and plants, so-called environmental DNA (eDNA). By collecting water samples and extracting and sequencing eDNA, the biodiversity of freshwater ecosystems can be accurately determined in a faster, less invasive process.
And since the DNA in rivers can be transported downstream for many kilometres, information on the numbers and density of organisms in an upstream catchment area can also be calculated.
Using mathematical models, Florian Altermatt and co-authors from the University of Zurich and the Swiss Federal Institute of Aquatic Science and Technology (Eawag) reconstructed the biodiversity patterns in detail for 740 km2 of the Thur River in northeast Switzerland. Their research was published in Nature Communications on 17 July 2020.