Mr Nicolas Restrepo1, Steve Wing1, Gert-Jan Jeunen2, Michael Knapp1, Sara Ferreira1, Neil Gemmell1
1University of Otago, , New Zealand, 2University of Plymouth, Plymouth, United Kingdom
Biography:
I am a PhD student at the University of Otago, New Zealand, working in marine molecular ecology and environmental DNA (eDNA). My research focuses on using eDNA and other molecular tools to understand how land-based stressors influence rocky reef and kelp forest biodiversity. My background is in marine biology, conservation genetics, and population genomics, with research experience spanning marine megafauna and coastal ecosystems in Colombia and New Zealand.
Abstract:
Marine heatwaves (MHWs) are increasing in frequency and intensity globally, with well-documented physiological and range-shift impacts on marine species, yet their signatures on whole-community composition over time remain difficult to detect using conventional monitoring approaches. Doubtful Sound, Fiordland, New Zealand, experienced a notable MHW event in 2023, offering an opportunity to examine whether archived environmental DNA (eDNA) samples can retrospectively resolve associated shifts in marine metazoan community composition. This study uses eDNA samples collected in 2016 and 2026, spanning the period before and after this MHW event, to investigate whether metabarcoding data can detect compositional changes in metazoan communities coinciding with acute thermal disturbance. Sequence data are being analyzed to characterize metazoan taxonomic composition and diversity across sampling periods, with comparisons made between pre- and post-heatwave time points. Given the retrospective nature of the dataset, this research also evaluates the extent to which historical eDNA samples, often collected without eDNA-specific replication in mind, can support robust inference of ecological change, and identifies methodological considerations for future retrospective eDNA studies. Findings will contribute to understanding whether eDNA can serve as a practical tool for reconstructing metazoan community responses to marine heatwave events using existing sample archives, with implications for long-term coastal biodiversity monitoring in data-limited historical contexts.