Miss Tian Tian1,2, Dr Xavier Pochon3, Mr Peter Bell1, Professor Maren Wellenreuther1,2
1Seafood Technologies, Bioeconomy Science Institute, Nelson, New Zealand, 2School of Biological Sciences, University of Auckland, Auckland, New Zealand, 3Citizens Of The Sea, Nelson, New Zealand
Biography:
Tian is a PhD student from the Joint Graduate School of University of Auckland and Plant and Food Research Institute, New Zealand, with backgrounds in Marine Ecology and Molecular Biology. Her current research focuses on biofouling community monitoring in aquaculture environments using eDNA technologies and machine learning. She aims to develop and optimise efficient and cost-effective tools and protocols to perform qualification and quantification analyses of community composition, and eventually provide fundamental advice on biofouling mitigation, aquaculture improvement and relevant policy making.
Abstract:
Diatoms are among the earliest colonisers of submerged surfaces and have been recognised as sensitive indicators of environmental change. However, their potential as bioindicators of marine biofouling development remains unexplored. Specifically, this talk will describe how a diatom-specific rbcL metabarcoding marker was used alongside 18S rRNA metabarcoding of broader eukaryotic communities to investigate whether diatom assemblages respond concordantly with marine biofouling communities across seasonal, wave exposure, depth, and substrate gradients.
Diatom communities exhibited strong concordance with the overall biofouling assemblages (Procrustes correlation, r = 0.83–0.87, p < 0.01), with both markers identifying season and wave exposure as the primary drivers of community composition. Substrate, depth, and deployment duration had weaker but statistically significant effects. Network analyses further identified consistent associations between dominant diatom families, including Naviculaceae and Bacillariaceae, and key macrofouling classes such as Hydrozoa and Malacostraca across environmental conditions. While these associations do not directly represent their ecological interactions, they demonstrate that diatom communities respond in parallel with broader biofouling assemblages to environmental variation.
This talk will also discuss the value of combining complementary metabarcoding markers to characterise different components of complex marine communities. Together, these findings provide an important step towards developing diatom-based bioindicators for marine biofouling surveillance, biosecurity, and ecosystem management.