Scientists have developed a new method for measuring biodiversity in river systems. By measuring environmental DNA found in rivers, the research team was able to extract information on the diversity and quantity of different species. The details are in a paper just published in the journal Nature Communications.
The biodiversity of a river is a good indicator of the ecosystem’s health. Pollution, climate change, and other problems tend to change the diversity and quantity of species present. Traditional methods for conducting a river census involve manually collecting and identifying animals. It’s tedious work and takes up a lot of time and money.
A team of researchers investigated possible alternatives to manually collecting organisms. They had the idea to analyze environmental DNA—DNA that is shed into the environment through skin cells, feces, and other biological sources. This eDNA persists in the environment and can be collected and then sequenced.
The team collected water samples from the Glatt river in Switzerland. They analyzed the samples on a computer, using databases to determine which species were present. With one liter of collected water, the team could determine a wide variety of species, both aquatic and terrestrial. The researchers then compared their results to data gathered using traditional methods. The two methods were comparable, with the eDNA strategy providing a more comprehensive picture since it included native land-dwelling animals. The eDNA method was cheaper and much faster than classic sampling methods.
Regularly measuring the biodiversity of aquatic ecosystems is critical for judging the health of the environment. Past river census methods were labor-intensive and involved manually collecting species with kicknets. The research team’s new method, using eDNA, is simpler and less expensive. The team was able to identify the species present in the area, including terrestrial animals such as beavers, by collecting a small water sample. The team hopes that their findings will help scientists better analyze the biodiversity of rivers and other freshwater systems.
Kristy Deiner et al. Environmental DNA reveals that rivers are conveyer belts of biodiversity information. Nature Communications (2016).