The health of aquatic ecosystems is at the heart of discussions on biodiversity and climate change, especially with regard to eutrophication – the excessive accumulation of nutrients that degrades water quality and reduces biodiversity.
Measuring the trophic state, which indicates the degree of eutrophication of a lake, is essential for the effective conservation of these ecosystems. However, traditional methods, which require frequent sampling of nutrients and organisms over a period of years, are time-consuming and expensive.
Innovation in biodiversity monitoring in lakes with environmental DNA without taxonomy
Researchers from New Zealand [1] propose using environmental DNA (eDNA) extracted from lake sediments to monitor trophic status, focusing on diatoms, a group of microalgae particularly useful for measuring the level of eutrophication due to their sensitivity to nutrient variations.
The solution proposes the use of environmental DNA (eDNA) without the need to classify organisms by species or genus. This simplifies analysis and eliminates dependence on DNA sequence databases, overcoming the taxonomic impediment – the difficulty of identifying and naming organisms in poorly studied regions.
By using eDNA without taxonomy, the method makes it possible to capture the greater genetic diversity present in the environment, including unknown organisms or those not catalogued in DNA databases. This represents an evolution in the monitoring of aquatic ecosystems, allowing for rapid and accurate analysis, which is essential for effectively conserving and restoring biodiversity.
Field-validated results: accurate monitoring of eutrophication levels in lakes using eDNA
In the study, 89 New Zealand lakes were analyzed using three methods: traditional morphological identification, eDNA with species assignment and eDNA without species assignment(taxonomy-free). The method using taxonomy-free eDNA proved to be the most accurate, explaining 85% of the variability in eutrophication levels with the smallest margin of error of the three methods. It also detects greater ecological diversity, which is often lost in taxonomy-based approaches.
Another important point is that by using lake bottom sediments – which accumulate data over time – this technique offers an integrated view of years of environmental variation, eliminating the need for repetitive seasonal sampling.
Impact of environmental DNA on efficient monitoring of biodiversity and eutrophication in lakes
This method offers a robust and accessible tool for monitoring the health of aquatic ecosystems and better understanding changes in biodiversity over time. By making monitoring more efficient, it enables the monitoring of more lakes and facilitates the implementation of conservation and ecosystem restoration measures, providing a significant advance for environmental management.
Conclusion: the future of monitoring aquatic ecosystems with environmental DNA is taxonomy free
With this new technique, monitoring the biodiversity and trophic state of lakes has never been so accessible, fast and accurate. If you work in environmental management, ecosystem restoration or are looking to integrate biodiversity solutions into your carbon projects, now is the time to explore the use of eDNA.
Contact us to find out how we can help your company implement this innovative technology and transform the way you monitor biodiversity and environmental assets.
For more details on the study, go here and read the full article:
Reference:
[1] Gregersen, R., et al. (2023). A taxonomy-free diatom eDNA-based technique for assessing lake trophic level using lake sediments. Journal of Environmental Management. https://doi.org/10.1016/j.jenvman.2023.118885