Prof. Grant Hose1, Dr Paul Greenfield2, Dr Kathryn Korbel1
1School of Life and Environmental Sciences, The University of Sydney, Camperdown, Australia, 2Energy Research Unit, Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, Australia
Biography:
Copilot said:
Grant Hose is an aquatic ecologist and ecotoxicologist whose research explores how groundwater ecosystems, and their invertebrate and microbial communities, respond to environmental change. His team combines field surveys, laboratory experiments, groundwater invertebrate taxonomy, and environmental DNA (eDNA) approaches to uncover both the drivers and consequences of ecological change. This work has established an international reputation in groundwater ecology and advanced new tools for assessing ecosystem health and condition. His current research focuses on groundwater biodiversity, ecosystem health assessment, ecological risk and ecotoxicology, and the critical ecosystem services provided by groundwater fauna.
Abstract:
The use of environmental nucleic acids (eNA) has transformed biodiversity assessment and ecological monitoring, particularly in groundwater ecosystems where traditional sampling is challenging, costly, and often fails to detect rare or cryptic taxa. While environmental DNA (eDNA) is now widely used due to its stability and ease of analysis, environmental RNA (eRNA) has been proposed as a potentially more accurate indicator of active biological communities. However, its utility for groundwater monitoring remains largely untested.
In this study, we compared co-extracted eDNA and eRNA recovered from groundwater samples to determine which approach is currently most suitable for assessing groundwater biodiversity. We found significant differences between the communities characterised by each method. eDNA consistently produced higher read counts, greater taxonomic richness, and distinct community profiles compared with eRNA. In contrast, eRNA concentrations were frequently too low for successful sequencing, limiting its effectiveness for routine groundwater surveys.
These findings highlight an important challenge for groundwater ecologists: although eDNA may include dormant, inactive, or relic DNA, the practical limitations of eRNA in inherently low concentration DNA environments currently restrict its widespread application. We suggest that eDNA remains the most robust and cost-effective tool for groundwater monitoring. Furthermore, relic and dormant DNA may provide valuable insights into ecosystem resilience and microbial seed banks, offering a broader perspective on ecosystem function and recovery potential than active communities alone.