[DLS] Avi Flamholz (Caltech)

“Studying Microbial Physiology to Predict the Fate of Soil Carbon”

The largest annual fluxes in the global carbon (C) cycle are biological. This is especially true on land, where plants catalyze virtually all photosynthesis and diverse microbial communities in soils and sediments carry out terrestrial respiration. A single gram of soil typically contains 10⁷–10¹⁰ microbes representing thousands of species, yet, depending on the circumstances, may sequester or liberate CO₂ over time. Must we document and model this amazing biological complexity to predict the fate of soil carbon? Climate models already disagree on the sign of soils’ future contribution to CO₂ emissions. Explicitly modeling microbes exacerbates this problem by proliferating parameters in a data-poor setting, making fitting and interpretation even more challenging. In this talk, I will advance a different approach. Drawing on experiments, theory, and computation, I will describe principles of microbial physiology and ecology that simplify, rather than complicate, models of soil carbon. These principles argue for a statistical view, where distributions of degradation rates are modulated by the environment — by temperature, water, pH, and nutrient limitation. This perspective shift also suggests a novel role for microbiology in climate science, one where we use the power of DNA sequencing to treat microbes as “sensors” of their local chemical environments.

[DLS] EAPS Department Lecture Series 

Weekly talks aimed to bring together the entire EAPS community, given by leading thinkers in the areas of geology, geophysics, geobiology, geochemistry, atmospheric science, oceanography, climatology, and planetary science. Runs concurrently with class 12.S501. 

Contact: eapsinfo@mit.edu