Yayla Sezginer

Through photosynthesis phytoplankton play an important role in the global carbon cycle, transferring an estimated 5-12 PgC annually from the atmosphere to the deep ocean via the biological carbon pump. Quantifying phytoplankton productivity is therefore critical for accurate carbon accounting. My research focuses on using autonomous chlorophyll fluorescence (Fast Repetition Rate Fluorometry; FRRF) to measure phytoplankton productivity and photo-physiology. These high frequency fluorescence measurements enable us to resolve phytoplankton responses to their environment over fine spatiotemporal scales (e.g. sharp hydrographic fronts or short-term changes in light conditions) that can be challenging to capture with current remote sensing or traditional bottle incubation techniques. The FRRF system is simple to deploy, and over the course of my degree (started in 2021) I have had the opportunity to collect measurements on research vessels and 'ships of opportunity' in diverse marine environments including the California Current, Southern Ocean, Canadian Arctic Archipelago, and Patagonian Fjords where phytoplankton are subject to very different environmental stressors.