Ms Lisa Chandler1,2, Dr Andrew Harford1, Professor Grant Hose3, Dr Chris Humphrey1, Professor Jenny Davis2
1Office Of the Supervising Scientist, Dept Climate Change Energy the Environment and Water, Eaton, Australia, 2Charles Darwin University, Casuarina, Aus, 3Macquarie University, Sydney, Australia
Biography:
Lisa Chandler is a PhD candidate within the College of Engineering, IT and Environment under supervision of Professor Jenny Davis and working with the Office of the Supervising Scientist of the Department of Climate Change, Energy the Environment and Water. Her research focuses on assessing the response of groundwater invertebrate and microbial communities to mine-derived stressors in a seasonal sandy stream. She has 20 plus years' experience in aquatic ecology research and monitoring, specialising in freshwater invertebrates, in both government and private sectors. Her research interests include macroinvertebrate taxonomy, the use of aquatic macroinvertebrates as indicators of disturbance and recovery, use of macroinvertebrates in ecotoxicology and general aquatic and groundwater ecology studies.
Abstract:
Eukaryotic communities in groundwater may be particularly sensitive to disturbance because they are adapted to relatively stable environmental conditions and have a narrow spatial distribution. Characterising these communities using traditional methods is generally limited to a small proportion of the whole community because taxonomic information is often limited, morphological identification is often time consuming, and many microeukaryote taxa are difficult to isolate and culture. In this study we examined eukaryotic community composition in shallow sand bed aquifer in a wet-dry tropical environment, using traditional stygofauna sampling methods and environmental DNA (eDNA), as part of a broader ecological risk assessment for shallow groundwater communities exposed to mine-water impacts. The aquifer had a gradient of contamination from Mg and SO₄ dominated, saline mine-water. Sampling occurred during the dry season when only subsurface water was present. Groundwaters were collected from piezometers (approximately 2m in depth), located in the creek channel upstream and downstream of the mine-water influence. Traditional morphological assessment (from net samples) and next generation sequencing of eDNA was used to analyse the eukaryote assemblages. With the molecular data we observed significant changes in community composition with exposure to mine-waters, however this was not reflected in the data from the stygofauna sampling. The changes in eDNA-based assemblage data were most strongly correlated with concentrations of SO₄, Mg and Na, as well as water table level. These findings indicate that studies based only on traditional stygofauna sampling methods may be limited in their ability to detect community changes for impact assessments.