Redox potential shapes the chemical composition of the subsurface biosphere
Room E001
Abstract
The extent of subsurface microbial life and its response to climatic and anthropic forcing depends on its relationship with environmental conditions. For microbial metabolisms to be competitive in low-energy environments, evolutionary theory suggests that the energy required to build up macromolecules through anabolism must be minimal. To test this hypothesis, I developed a thermodynamic model of protein chemical activitiy, based on metagenomic data from peat soils.
The correlation between the carbon oxidation state of proteins, their redox potential of maximum activities, and the taxonomic abundance is consistent with thermodynamic predictions. This is a paradigm shift. Biomass synthesis is often thought to violate the 2nd law of thermodynamics which stipulates ever-increasing entropy. In this seminar, I will show that there is a minimization of free energy consumption during anabolism, such that thermodynamic forcing imposed by environmental conditions shapes the chemical composition of subsurface microbial communities.