Dr Maria Gomez Cabrera1,2, Dr Jin Yan Lim1, Dr Marko Terzin1,3, Dr Neal Cantin1, Professor David Bourne1,2,4, Dr Yun Kit Yeoh1,2, Dr Patrick Laffy1,2, Dr Sven Uthicke1,2
1Australian Institute of Marine Science, Townsville, Australia, 2AIMS@JCU, Research Division, James Cook University, Townsville, Australia, 3Melbourne Integrative Genomics, School of Mathematics and Statistics, University of Melbourne, Parkville, Australia, 4College of Science and Engineering, James Cook University, Townsville, Australia
Biography:
Dr Maria Gomez Cabrera is a marine scientist specialising in molecular ecology, environmental DNA (eDNA), coral reef ecology and marine biodiversity. She holds a PhD in Marine Science from The University of Queensland, where she investigated coral–dinoflagellate symbiosis. Her research has explored coral reef functioning, the reconstruction of past reef communities and more recently the study of Crown-of-Thorns seastar ecology and the use of eDNA as a monitoring tool.
Abstract:
Environmental DNA (eDNA) is transforming marine biodiversity research by providing a complementary approach to conventional ecological monitoring. By analysing genetic material collected from seawater, eDNA enables broad-scale detection and characterisation of biological communities without direct observation. Integrating eDNA with established monitoring programs may therefore provide new insights into ecosystem responses to environmental disturbances. Here we assess the potential for eDNA to complement the long-term monitoring of the Great Barrier Reef (GBR), which the Australian Institute of Marine Science (AIMS) has carried out for over 40 years.
Seawater samples were collected at three timepoints from four northern and two central GBR reefs between November 2023 and January 2025, spanning periods before, during, and after the 2024 mass bleaching event. Samples were analysed using 18S V4 and COI metabarcoding to characterise eukaryotic assemblages across reefs experiencing contrasting levels of thermal stress, bleaching severity, and subsequent ecological impacts. Of 2,015 18S amplicon sequence variants (ASVs), 95 were differentially abundant across bleaching phases, dominated by Dinoflagellata (32 ASVs) and Diatomea (17 ASVs). Eukaryotic community composition differed significantly among reefs and sampling periods, with reef location explaining the greatest proportion of variation and the strongest temporal shift occurring between bleaching and post-bleaching sampling.
These results demonstrate that eDNA can detect changes in the composition and relative abundance of eukaryotic taxa represented in reef seawater, extending assessments of bleaching-associated change beyond corals alone. eDNA metabarcoding could therefore complement established reef monitoring by providing broader insight into ecosystem changes associated with climate-driven disturbances.