Ms Bobby Lust1, Ms Amy A. Gault1, Dr Megan R. Shaffer1, Dr Shaun P. Wilkinson1
1Wilderlab NZ Ltd, Miramar, Aotearoa New Zealand
eDNA sampling methods comprise a variety of techniques, including active and passive filtration, each of which has advantages and disadvantages. Currently, the majority of riverine eDNA assessments across Aotearoa New Zealand are carried out using positive-pressure syringe filtration kits, which are portable, easy to use, and have been extensively validated through high-replication analysis across a network of well-characterised monitoring sites. However, snapshot samples taken using active filtration methods can only target DNA that is available at a single point in time, and can miss rare and distant organisms, those with diurnal migration patterns, or those with sporadic contact with the water, e.g. birds and mammals. To increase sensitivity and expand the effective detection distance for eDNA monitoring, we developed a single-use passive sampler, which is deployed in flowing water for 24 hours before retrieval and sample fixation. Field trials carried out at multiple riverine sites across Aotearoa New Zealand showed a more than two-fold increase in the number of species detected and in the total number of unique amplicon sequence variants (ASVs) compared to the syringe filtration kit. Additionally, the passive sampler offers a higher capture rate of previously harder-to-detect terrestrial species, and allows for more reliable post-sequencing processing such as biodiversity index calculations. Although limited to flowing water and requiring an additional site visit for retrieval, the passive sampler kit is a valuable addition to the eDNA toolkit, and seems well suited to applications such as riverine threatened species monitoring, biosecurity surveillance, community-based science programmes and ecological health assessments.
Biography:
After completing a BSc in Biology in my home country, the Netherlands, I decided to pursue a MSc in Marine Biology in Stockholm, Sweden. For both these degrees I was able to participate in coral reef research projects at the University of Queensland in Australia. These projects helped deepen my love for the ocean, and in turn I also became an avid scuba diver. I am an ADAS certified Scientific Diver, and currently in the process of finishing my TDI Dive Master. In 2017 I moved to Aotearoa New Zealand to start my PhD at Victoria University of Wellington, where I worked on another coral symbiosis project with an extensive molecular component, such as metabolomics and proteomics. Having recently submitted my thesis, I started work at Wilderlab. Here, I am in charge of the laboratory flow and involved in many research and development projects, such as the development of new sampling methods and detection assays.