The “biological pump” is the suite of biogeochemical processes that lead to carbon sequestration in the deep ocean, out of contact with the atmosphere, and is an important regulator of global climate. This seminar will review the seminal works that have sought to understand and quantify the component processes: (1) production of organic carbon by photosynthetic plankton in the sunlit surface ocean; (2) aggregation of organic matter into sinking particles; (3) degradation of those particles over depth. We will then review evidence for the changing strength of the biological pump over Earth’s history, and the attempts to predict its response to current climate warming.
Over the last few decades, numerical biogeochemical models have provided new insights into the marine carbon cycle, its contribution to past climate change, and its potential responses to future climate warming. In this practical class, students will build simple biogeochemical models – ranging from box models of marine microbial ecosystems to three-dimensional nutrient cycling models – and design experiments to address climate change hypotheses. They will also be taught to analyze output from state-of-the-art climate models used by the Intergovernmental Panel on Climate Change. No prior computing experience is required: an extensive grounding will be provided in the MATLAB programming language that will be used throughout the course. By participating, students will not only learn invaluable programming skills, but also gain a deeper intuition of the ocean carbon cycling and its role in the global climate system.