Dr Mieke Van Der Heyde1, Dr Nicole White1, Jason Alexander1, Dr Paul Nevill1, Prof Andrew Austin2,3, Dr Nicolas Stevens4, Matt Jones5, Dr Michelle Guzik2,3
1Trace and Environmental DNA Laboratory, Curtin University, Bentley, Australia, 2South Australia Museum, Adelaide, Australia, 3Australian Centre for Evolutionary Biology and Biodiversity, School of Biological Sciences, The University of Adelaide, Adelaide, Australia, 4Bestiolas Consulting, Jolimont, Australia, 5Enpoint Consuting, Fremantle, Australia
The impacts of anthropogenic climate change, extraction and pollution on groundwater pose major threats to groundwater ecosystem health, prompting the need for efficient and reliable means to monitor subterranean communities. Traditional survey techniques for subterranean fauna relies on trapping organisms and morphological identification, which can be biased, labour intensive, and often indeterminate to lower taxonomic levels. Environmental DNA (eDNA)-based methods have the potential to dramatically improve existing stygofaunal survey methods, but currently rely on time consuming active filtration of water, limiting the number of samples that can be processed. Passive eDNA sampling-submersion of an absorbent material (e.g. filter membrane, sponge etc.) into the environment-has previously shown promise as an alternative to active filtration in surface aquatic ecosystems. Here, we compared groundwater eDNA collected from active filtration of groundwater samples to passive submersion of membranes (10 minutes and 24 hours); and specimens morphologically identified from bores at two geographically distinct locations in Western Australia. Our results show that while the relative abundance of eDNA in groundwater (measured through qPCR) is lower in passive samples, the species diversity detected is comparable between active and passive eDNA sampling techniques. Additionally, metabarcoding of passive eDNA samples detected the majority of subterranean orders identified morphologically (12/17). Detection accuracy could potentially be improved with increased sampling intensity and application of DNA extraction methods that improve DNA yield. The findings of this study demonstrate that passive eDNA sample collection has the potential to improve subterranean eDNA surveys by increasing replicability and efficiency while also reducing costs.
Biography:
Mieke is currently a Research Associate with the Trace and Environmental DNA (TrEnD) Laboratory. Her research focus is developing and applying eDNA methods to monitor terrestrial and subterrestrial ecosystems. Mieke completed her PhD in 2020 with the ARC Centre for Mine Site Restoration (CMSR) and the TrEnD Labs. Her research focussed on the application of eDNA surveys to monitor soil microbes, vertebrates, invertebrates, and plants during mine site restoration. In late 2020, Mieke started her post-doc position at Curtin studying underground communities living in the groundwater (stygofauna).