CBIOMES study reveals genetic strategy helping diatoms survive changing ocean conditions.
Reporting by Helen Hill for CBIOMES
As global temperatures rise, marine ecosystems face unprecedented challenges. A new study published in Nature Climate Change by Zhengke Li, Yong Zhang, Andrew J. Irwin, and Zoe V. Finkel reveals that diatoms—microscopic algae critical to ocean food webs—may have a surprising evolutionary advantage: polyploidization.
Diatoms are responsible for roughly 20% of global carbon fixation, making them essential players in regulating Earth’s climate. Understanding how these organisms respond to warming oceans is vital for predicting future ecosystem dynamics. The research team investigated whether polyploidization—the duplication of entire genomes—could accelerate diatom adaptation to temperature stress.
Polyploidization occurs when an organism acquires extra sets of chromosomes, a process well-documented in plants but less understood in marine microbes. This genetic redundancy can provide raw material for evolution, allowing organisms to experiment with new traits without losing essential functions. “Polyploidization is like giving diatoms a genetic toolkit with extra spare parts,” explains lead author Zhenke Li. “Those additional copies of genes can mutate and adapt more rapidly, which is crucial under environmental stress.”
To test this idea, the researchers combined laboratory experiments with computational modeling to explore how polyploid diatoms respond to warming compared to their diploid counterparts. They exposed populations of Thalassiosira species to elevated temperatures over multiple generations, tracking growth rates, photosynthetic efficiency, and genomic changes. The results were striking: polyploid diatoms adapted to warming conditions significantly faster than diploids. Within just a few hundred generations, polyploids exhibited higher thermal tolerance and maintained robust growth, while diploid populations showed signs of stress and decline.
This discovery has far-reaching implications. Diatoms form the base of marine food webs and play a key role in carbon sequestration. If polyploidization enables them to thrive in warmer waters, it could stabilize primary production in some regions. However, the researchers caution that adaptation may not be uniform across species or ecosystems. “Polyploidization doesn’t guarantee resilience everywhere,” notes co-author Zoe Finkel. “It’s one piece of a complex puzzle involving nutrient availability, ocean circulation, and interactions with other organisms.”
Beyond its ecological significance, the study sheds light on evolutionary mechanisms in microbial life. Genome duplication has long been recognized as a driver of innovation in plants and animals; this work suggests similar dynamics in marine phytoplankton. “Polyploidization could be a hidden engine of adaptability in the ocean,” says Andrew Irwin. “Understanding these processes helps us anticipate how marine ecosystems will respond to climate change.”
The team plans to investigate whether polyploidization influences other stress responses, such as acidification and nutrient limitation. They also aim to explore how widespread polyploidy is among diatom species in natural environments. As climate change accelerates, insights like these are critical for refining global models of carbon cycling and ecosystem resilience. Diatoms may be small, but their evolutionary strategies could have planetary-scale consequences.
Publication:
Zhengke Li, Yong Zhang, Andrew J. Irwin, Zoe V. Finkel (2025), Polyploidization in diatoms accelerates adaptation to warming, Nat. Clim. Chan., doi: 10.1038/s41558-025-02464-1