SEMINAR: Sara Ferrón – “Plankton metabolism in the oligotrophic ocean”
Aquatic photosynthesis and respiration rates regulate the flux of organic matter into the ocean’s interior, a process that influences Earth’s climate by effectively sequestering carbon dioxide from the atmosphere. This flux of organic matter also serves as the primary energy source to marine organisms inhabiting the dark depths of the ocean. However, determining and predicting the magnitude of microbial metabolic rates in the ocean presents challenges, and the accuracy of available techniques is difficult to assess given the lack of standards against which to compare measured rates. Methodological limitations and sparse oceanic measurements contribute to our inadequate understanding of the controls on plankton metabolism, hindering our ability to predict changes in the biological carbon pump. In this seminar, I will discuss my efforts to address some of these challenges and to constrain plankton metabolic rates in the North Pacific Subtropical Gyre. I use a variety of approaches, each with its own methodological advantages and limitations, that measure different steps within the spectrum of metabolic processes going from solar energy capture to the breakdown of organic matter. My research has revealed pronounced seasonality in the net production of organic matter within the euphotic zone, despite the chronic oligotrophy year-round. Annual net community production exceeds estimates of carbon export by sinking particles, suggesting that the contribution of other export mechanisms to the biological carbon pump might be important.
Thursday, April 4, 2024, 3:00p.m., MSB 100
