Can cyanobacteria use organic nutrients to thrive in future oceans?

Marine picocyanobacteria are central to regulating the global climate and marine food webs as key photoautotrophic primary producers. Increasing evidence suggests picocyanobacteria can uptake diverse organic nutrients to supplement autotrophy, thus adopting a mixotrophic lifestyle. Yet, the extent of mixotrophy in picocyanobacteria and its role in shaping picocyanobacterial assemblages in the global ocean remains almost entirely unknown. Using transformative, high-throughput biochemical and eco-physiological approaches, we will systematically characterise organic nutrient uptake in picocyanobacteria. Our molecules-to-ecosystems approach will transform our understanding of alternative nutrient acquisition in picocyanobacteria and the role of mixotrophy in shaping picocyanobacterial populations in a rapidly-changing ocean landscape, serving as a blueprint for other key microbial primary producers.