NOAA 'Omics Seminar Series (March 21, 2024): Marine Heatwave Drives Shifts in Pelagic Microbiology

Title: A marine heatwave drives significant shifts in pelagic microbiology: A story based on a decadal national effort of marine microbiome observations and community environmental indices.
Presenter: Dr. Jodie van de Kamp & Dr. Levente Bodrossy
Abstract: Marine heatwaves (MHWs) cause disruption to marine ecosystems, deleteriously impacting macroflora and fauna. However, effects on microorganisms are relatively unknown despite ocean temperature being a major determinant of assemblage structure. Using data from thousands of Southern Hemisphere samples, we reveal that during an “unprecedented” 2015/16 Tasman Sea MHW, temperatures approached or surpassed the upper thermal boundary of many endemic taxa. Temperate microbial assemblages underwent a profound transition to niche states aligned with sites over 1000 km equatorward, adapting to higher temperatures and lower nutrient conditions bought on by the MHW. MHW conditions also modulate seasonal patterns of microbial diversity and support novel assemblage compositions. The most significant effects of MHWs on microbial assemblages occurred during warmer months, when temperatures exceeded the upper climatological bounds. Trends in microbial response across several MHWs in different locations suggest these are emergent properties of temperate ocean warming, which may facilitate monitoring, prediction and adaptation efforts. In this talk we will introduce the Australian Microbiome, a standardized, integrated observatory of marine and terrestrial microbiomes, the IMOS Marine Microbiome Facility which has been providing national scale microbiome observations for more than a decade across Australia’s coastal oceans and the development and potential use of species and community environmental indices for ecological monitoring.