29.04.2024

The water quality of large rivers such as the Rhine, Neckar and Donau is regularly analysed. But what about the small streams that meander through meadows and fields? We know very little about them. The ecological status of our streams is rarely recorded, even though they make up around 70 per cent of our 500,000 km of flowing waters. In the ARD join-in campaign #UnsereFlüsse, presenter Jessy Wellmer calls on us to work together to close this knowledge gap. Professors Florian Leese and Daniel Hering from the UDE are supporting the campaign as scientific advisors.

According to the Federal Environment Agency, only eight per cent of German rivers are ecologically healthy. And what about the small streams? "Let's find out together during the hands-on campaign," says Prof Dr Florian Leese. Together with a team from the Centre for Water and Environmental Research (ZWU), the expert in aquatic biology will analyse the biodiversity in selected streams and rivers. "We are analysing the so-called environmental DNA. Environmental DNA refers to fragments of genetic material that are released into the environment by living organisms. For example, through faeces or skin residues." The DNA collected can be used to make very precise statements about which animals live in a stream without catching just one fish or frog.

"The collected DNA is sequenced in the laboratory; we use the environmental DNA metabarcoding method," explains Leese. The method involves filtering the water samples collected in the hands-on activity and isolating the DNA fragments from the water, then amplifying them using a polymerase chain reaction and reading out the sequence of letters ('sequencing'). The sequences give the researchers an insight into the organisms that live in the water without having to catch the organisms themselves.

"What is more important in the ARD join-in campaign, however, is the active participation of as many people as possible in nature itself in order to collect important data on the condition of the waters. These surveys are no substitute for expert assessments, but they do provide important additional data, for example on the drying up of water bodies and the impact of renaturalisation measures," says Florian Leese.

Anyone can take part in the ARD participation campaign. Take a questionnaire with you, go to the nearest stream in the woods or meadow and examine the little river. Does it flow freely and in curves, are the banks natural? The questionnaire guides the participants through a systematic analysis of the river. The stream assessments will be published on a map of Germany at DasErste.de/unsereFluesse. In addition, 30 streams will be selected to be analysed by the UDE team with regard to their biodiversity.

The UDE has a unique focus in Germany in the field of water research. Over the past two decades, researchers from the disciplines of biology, chemistry, medicine, engineering, humanities and social sciences have developed excellent inter- and transdisciplinary collaboration.

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