Sensor for Biodiversity – Great Hope: Determining Biodiversity Thanks to DNA Snippets – Knowledge


A research project at ETH Zurich is exploring the possibilities of a new method for identifying species. It is based on the detection of DNA snippets in the environment. Scientists around the world have high hopes.

The boat sways slightly as Kristy Deine bends down and fills the sample container with some water from Lake Hallwil. The professor of environmental DNA at ETH Zurich has a vision: she wants to take global species protection a decisive step forward. And the seawater sample is the key.

Environmental DNA is fascinating because it feels like capturing all the stars in the universe at once

DNA floats in water – whole and in fragments. Lots of it. That’s what the molecular ecologist is aiming for. Because the DNA reveals who lives in and around Lake Hallwil. “Environmental DNA is fascinating because it feels like capturing all the stars in the universe at once,” Dein enthuses.


Kristy Deine is one of only three environmental DNA professors in Europe


Complex, time-consuming and expensive

So far, monitoring biodiversity has been complex and expensive. Plant, fungus and animal species or their legacies are collected, caught, counted and mapped at regular intervals, sometimes lasting weeks. As a result, the data collected are hardly comparable, which often makes it difficult to cover an area uniformly.

Environmental DNA – also known as environmental or eDNA – enables the recording of biodiversity quickly, easily and inexpensively. And all species are recorded using the same method.

Traces in the environment reveal presence

Every living being permanently leaves traces of its individual genetic information in the environment. Leaves, feces, feathers, mucus – DNA is everywhere. This can be collected and then sequenced. The result is a long list of DNA sequences, i.e. sequences of letters.

In order to find out from which species the individual sequence originates, a comparison of these with sequences stored in DNA comparison databases is necessary. The problem: The databases are incomplete. The sequences of numerous species are missing. However, various ambitious projects want to change this in the next 10 years.

Paradigm shift in research

For Kristy Deine, the potential of the method is therefore not in question. “For scientists, biologists and ecologists, this is really a paradigm shift because we now have access to information that we have never had before.” The first practical applications are also promising.

application in practice

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Environmental DNA is already being used successfully in practice when it comes to finding rare or non-native species. For example, the canton of Aargau is pursuing a neobiota protection program on Lake Hallwil. Measures are intended to prevent invasive species such as quagga mussels or freshwater shrimp from entering the lake.

Instead of regularly searching the entire lake for the species under observation, the cantonal biologists take water samples to check their effectiveness. They then check these specifically for the DNA of the species they are looking for. Their DNA sequences are already well documented and can therefore be easily compared in the databases. The big advantage: actual visual contact with the species is not necessary. Their DNA already reveals their presence.

But a lot more is possible, Kristy Deine is convinced. Their goal is broad, large-scale applications. Because DNA is mobile, she assumes that the entire biodiversity in the entire watershed of a lake can be recorded with environmental DNA.

“Once DNA gets into water, it migrates with the water. It’s easy to imagine DNA going into a river and then flowing to the lake, so the lake acts like a sponge that sucks up all the DNA. And it’s probably been around long enough for us to collect it. The information that we get is for the entire watershed,” explains Deine.

watershed principle

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The Hallwilersee has a catchment area of ​​128 square kilometers.


The water of a lake is determined by the watershed – the point on land where water flows in one direction or the other. The Hallwilersee has a water catchment area of ​​128 square kilometers.

All in all, Kristy Deines and his team are investigating eight lakes of roughly the same size, but with water catchment areas of different sizes. The larger the catchment area, the greater the diversity of species to be found.

There are a good 1.4 million lakes worldwide, which cover a good 25 percent of the earth’s surface through their catchment areas. By simply taking water samples, the biodiversity of an immensely large area could be recorded in the future. Kristy Deine is already in contact with researchers worldwide to make her vision a reality as quickly as possible.

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