AFTER THE APOCALYPSE: HOW UNPRECEDENTED HEAT WAVES LEAD TO UNPRECEDENTED PHYTOPLANKTON COMMUNITIES

One of the most alarming consequences of ocean warming is the increasing frequency and intensity of extreme regional marine heatwaves (MHW). Episodic MHWs now regularly approach or exceed the upper thermal limits of resident phytoplankton species as determined by laboratory reaction norm studies, yet very little is known about the actual consequences for long-term phytoplankton community diversity and function in natural ocean environments. Despite this unfolding climate emergency, uncertainty remains about whether microbial assemblages can fully rebound from these damaging transitory events. Understanding this critical ecosystem recovery process requires learning how resilience to extreme temperatures varies among and within phytoplankton taxa, from major functional groups down to individual species. Recent experimental and observational research suggests that varying abilities to survive and recover from temporary extreme thermal stress can profoundly reshape post-MHW marine microbial communities by selecting for heat-tolerant groups, and even for thermally-resistant subpopulations within a single species. This talk is intended to offer a window into the future ocean where differential resilience to MHWs will reshuffle phytoplankton communities in novel ways, with implications for changing food webs and biogeochemical cycles in marine regimes around the world.

Presentation Preference: Oral

Primary Presenter: David Hutchins, University of Southern California (dahutch@usc.edu)

Authors:

David Hutchins, University of Southern California  (dahutch@usc.edu)

Yutong Chen, University of Southern California  (yutongc@usc.edu)

Feixue Fu, University of Southern California  (ffu@usc.edu)

Tatiana Rynearson, University of Rhode Island  (rynearson@uri.edu)