Grant: Discovery Grants Program - Individual

CO2 uptake and biological productivity in the oceans is driven by the photosynthesis of small phytoplankton cells, which are entrained in the water column. Phytoplankton, however, suffer ongoing light inactivation of their photosynthetic system, and to maintain activity they must counter this inactivation with repair through removal and replacement of damaged proteins. If the inactivation outruns repair the phytoplankton suffer inhibition of their photosynthesis which lowers their capacity to take up CO2 and therefore lowers marine productivity, ultimately with links back to atmospheric CO2. My NSERC research program is founded upon the conviction that quantifying this dynamic balance in phytoplankton is important to understand marine productivity and the likely responses of marine communities to environmental change. We are finding that phytoplankton strains isolated from diverse habitats show comparable susceptibility to the initial inactivation of photosynthesis, but have widely different capacities to repair and reverse the damage. This means that different phytoplankton have different abilities to withstand and exploit variable light in the environment, which can vary rapidly for a cell as it moves up or down in the water. The repair process is also sensitive to nutrients like nitrogen, UV and temperature, creating further interactions with the environment which we plan to investigate. A spin-off company, Environmental Proteomics, collaborates with my group and many others to create and distribute the detection systems necessary for this research.