Miss Panan Sitthirit1, Dr Annette Bolton1, Ms Judith Webber1, Mr Phil Abraham1, Mr Hayden Masterton1, Mr Murray Close1, Dr Louise Weaver1
1PHF Science, Ilam, New Zealand
Biography:
Panan Sitthirit is a Senior Technician and Environmental Microbiologist at PHF Science, New Zealand. Her research focuses on the biodiversity and ecology of groundwater ecosystems, with a particular interest in protozoa, free-living amoebae, and microbial communities. She applies both culture-based and molecular methods, including environmental DNA (eDNA), to investigate groundwater health and understand the movement and persistence of microorganisms in aquifers. Panan has contributed to several collaborative groundwater research projects aimed at developing biological indicators to assess and protect New Zealand's groundwater resources.
Abstract:
Groundwater is a crucial component of New Zealand's freshwater resources, supplying approximately 40% of the nation's water for irrigation and drinking. Despite its importance, groundwater monitoring primarily focuses on physical and chemical parameters, with no established biological indicators of aquifer health. Unlike surface waters, where macroinvertebrate community indices are routinely used to assess ecosystem condition, comparable biological assessment tools for groundwater are lacking due to limited baseline biodiversity information.
To address this gap, PHF Science has initiated groundwater biodiversity surveys across nine regions representing a range of aquifer types, including alluvial gravel, marble, coarse sand, and fractured basalt. This programme aims to develop a national biodiversity database and to explore relationships between biological communities and the physicochemical characteristics of aquifers.
This presentation focuses on protozoan communities identified in fractured basalt and coarse sand aquifers in Auckland and Waikato. Groundwater samples were analysed using both culture-based methods and environmental DNA (eDNA) sequencing. Both approaches revealed diverse protozoan communities, with eDNA detecting a broader range of taxa than culture-based methods. Conversely, culturing provided key insights into organism identity and potential ecological functions within aquifer ecosystems.
By integrating biodiversity with physical and chemical data, this research evaluates the potential of protozoan communities as indicators of groundwater health. The findings support the development of biological assessment tools to improve the monitoring, management, and protection of New Zealand's groundwater resources.