Phytoplankton response to climate change: Impacts on pools and fluxes of organic carbon

Phytoplankton connect light to life in the ocean. They regulate cycling of key elements and compounds, particularly carbon, in the ocean, supplying energy to the marine ecosystem and influencing atmospheric CO2 concentrations. Understanding how phytoplankton are responding to climate change is critical to predicting future changes in the Earth’s carbon cycle and for managing fisheries. In recent years, our capacity to monitor phytoplankton globally has advanced significantly. With 27 years of continuous global data acquisition, satellite remote sensing of ocean colour has become instrumental in examining climate impacts on surface phytoplankton. New ocean colour climate data records now offer more accurate estimates of long-term changes in phytoplankton abundance by incorporating information on the phytoplankton type present in the water. Additionally, the increased use of ocean robotics and innovative tools designed to study subsurface environments allow us to investigate phytoplankton communities at depth—beyond the reach of satellites—and understand how they, too, may be responding to climate change. In this project, my team will leverage these advancements to quantify how global pools and fluxes of organic carbon in the ocean, driven by phytoplankton, are reacting to climate change. By combining new ocean colour climate data records with in-situ data compilations and new understanding of subsurface phytoplankton, we will create climate data records of phytoplankton carbon and primary production throughout the sunlit zone of the ocean. These climate data records will be used with ecosystem models to study the effects of climate change on vertical changes in phytoplankton physiology, biomass and primary production. Our aim is to use these tools and datasets to deepen our understanding of changes in the ocean’s biological carbon pump and to study shifts in the flow of carbon from phytoplankton into the marine ecosystem. The data produced through this project will serve as a benchmark, enhancing climate models that forecast future changes in the marine carbon cycle and fish stocks.