A shared goal of astrobiology, ecology, and evolutionary biology is understanding the general principles governing spatiotemporal patterns in biological diversity. Exergonic metabolic diversity is the diversity of energy-yielding reactions harnessed by a living system. Because energetics shape the distribution and functioning of life, exergonic metabolic diversity is a fundamental dimension of biodiversity that is particularly relevant to astrobiology and biogeochemistry, as well as to understanding the macroecology and macroevolution of microbes.
In this seminar, I will present theory and data quantifying how chemical thermodynamics constrain patterns in the richness and turnover rate of the composition of exergonic metabolic reactions of organisms and ecosystems along environmental gradients such as pH, temperature, and oxygen. I will also provide a synthesis of the other factors, in addition to thermodynamics, that constrain exergonic metabolic diversity patterns, including chemical kinetics, biological scaling, and ecological and evolutionary dynamics. The developed theory elucidates the degree to which various physicochemical variables can influence exergonic metabolic diversity, with implications for the functioning of biogeochemical systems and patterns of functional, taxonomic and phylogenetic diversity in microbes.