Detecting marine pests using environmental DNA and biophysical models
Morgan R Ellis1, Zach S R Clark1, Eric A Treml2
1School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia; Deakin Genomics Centre, Deakin University, Geelong, Victoria, Australia.
The Science of the Total Environment
|November 18, 2021
Summary
Environmental DNA (eDNA) helps detect marine pests like kelp and seastars. This study reveals eDNA signals are localized, with detection limits around 750m, aiding pest surveillance efforts.
Area of Science:
- Marine biology
- Environmental science
- Molecular ecology
Background:
- Marine pest invasions are escalating globally due to increased trade.
- Environmental DNA (eDNA) offers a novel approach for pest surveillance by detecting genetic material in the environment.
- Understanding the spatial and temporal detection limits of eDNA in marine ecosystems is crucial but remains poorly understood.
Purpose of the Study:
- To assess the invasive ranges of the kelp Undaria pinnatifida and the seastar Asterias amurensis in south-eastern Australia using eDNA assays.
- To investigate the temporal and spatial detection limits of eDNA under varying oceanographic conditions.
- To combine eDNA decay estimates with biophysical modeling to understand eDNA dispersal and detection.
Main Methods:
- Utilized eDNA assays to survey for Undaria pinnatifida and Asterias amurensis in south-eastern Australia.
- Estimated eDNA decay rates for both species under laboratory conditions.
- Integrated eDNA decay data with biophysical models to simulate eDNA transport and predict detection limits.
Main Results:
- Positive eDNA detections at new locations suggest broader invasive ranges for both species than previously known.
- eDNA decay rates were similar for both species, with significant concentration decreases within 24 hours and undetectable levels after 3-4 days.
- Biophysical models indicated passive eDNA transport up to 10-20 km, with rapid concentration reduction within 1-3 km, confirming localized eDNA signals.
Conclusions:
- eDNA methods are valuable for marine pest surveillance, revealing wider invasive ranges.
- eDNA signals are generally localized, with detection limits influenced by local oceanography and sampling proximity.
- This research provides critical insights into the spatio-temporal detection limits of eDNA in marine environments, enhancing its application in biosecurity.
