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“Ocean Warming Threatens the Survival of Key Microbes”

Abstract: Marine microorganisms play a crucial role in fixing atmospheric CO2, producing biomass, recycling nutrients, and forming the foundation of the marine food chain. With the increasing temperature of oceans and scarcity of nutrients in the future, it is imperative to understand how these microbes will respond to these changes. While current global ocean biogeochemical models assume that microbial growth exponentially increases with temperature, this assumption has only been tested in model organisms and not in natural populations. To address this, we utilized population models and high-frequency observations to estimate microbial growth rates across ocean basins. Our findings reveal that the maximal growth rates of Prochlorococcus, which is the most abundant photosynthetic microbe in the ocean, are determined by temperature, with exponential growth from 13 to 27 degrees Celsius, followed by a sharp decline at higher temperatures. Our numerical modeling and resource competition theory predict that the negative impact of high temperatures on Prochlorococcus growth will lead to a 10% drop in primary production in the tropics without an evolutionary response, which could have significant implications for biogeochemical cycles.

Biography: François is a principal research scientist at the University of Washington, School of Oceanography where he leads a team developing flow cytometers, analytical tools and mathematical models to study marine ecosystems. He first studied Mathematics at the French Grande Ecole, then pursued a PhD in Population Biology and Oceanography with the Open University in London. François joined the University of Washington in 2008 leveraging laboratory experiments, field observations, and satellite data to build mathematical models that forecast microbial interactions across a range of ocean conditions.

The UW Data Science Seminar is an annual lecture series at the University of Washington that hosts scholars working across applied areas of data science, such as the sciences, engineering, humanities and arts along with methodological areas in data science, such as computer science, applied math and statistics. Our presenters come from all domain fields and include occasional external speakers from regional partners, governmental agencies and industry.

The 2022-2023 seminars will be virtual, and are free and open to the public.