Finding out what’s in our lake using eDNA
Environmental DNA (eDNA) has revolutionised how scientists monitor ecosystems and identify the species that live in them. eDNA is genetic material found in hair, scales, skin and even faeces (poo) that are naturally shed by living things into the environment.
DNA sequence for tuna and brown trout
When ‘fishing for eDNA’, students discover what is living in a lake by matching a short DNA sequence with the species it comes from.
Note: These are simulated DNA sequences rather than the actual sequence.
Every living thing has a DNA barcode – a short unique DNA sequence. Just like we scan barcodes to identify products in our shopping trolley, scientists look for DNA barcodes in samples of water from a lake, seawater, mud, ice or soil. They use the eDNA to identify individual organisms and monitor what’s living in a lake and even in the surrounding ecosystem.
This energetic activity simulates scientists fishing for (collecting) eDNA sequences from a lake system – housed in a plastic container outside – perhaps the school’s sports field or quad. Students match the eDNA sequences they collect with reference images and collate the data in a graph. Students are encouraged to peer review their results to build an accurate body of evidence.
eDNA explorers – discovering life in the lakes of Aotearoa
Environmental DNA (eDNA) is a useful technique for discovering what is living in or around a lake. The technology finds evidence of living organisms that we may not be able to see using our senses.
Questions for discussion
Why does Wiremu think that kōura are in the lake?
Why might it be difficult for Wiremu to find kōura?
How does eDNA help people learn about the presence of living things?
What are some of the advantages to using eDNA for lake monitoring?
Do you think there are any disadvantages to using eDNA for lake monitoring? What are the disadvantages?
In this activity, students use a magnetic fishing rod to collect information about the presence and population size of organisms living in their lake ecosystem. They use reference images to interpret and match the eDNA sequences and create a data collection chart of what’s living in the lake and the land around it and how abundant they are. Note: The activity uses simulated DNA sequences for each species.
By the end of this activity, students should be able to:
begin to recognise that all living things have a unique DNA barcode
begin to recognise that scientists can use these barcodes to identify what is living in a particular location
make inferences about why the DNA of non-aquatic species like cows or pine trees might be in a lake
make inferences about the condition of the lake as an ecosystem (its health)
discuss some of the advantages and disadvantages of using eDNA for ecosystem monitoring.
Download the Word file (see link below).
