PlantFun: How did the evolution of plants, microbial symbionts and terrestrial nutrient cycles change Earth's long-term climate?

Earth’s climate has undergone a series of dramatic changes over the Phanerozoic Eon (the last ~540 Million years), but the degree to which these changes were driven by the evolution of terrestrial plants and their microbial symbionts, as opposed to abiotic tectonic processes, remains unclear. We propose to combine targeted plant growth experiments and a new kind of fast spatial Earth system model to test the hypothesis that the evolving terrestrial biosphere and its effects on carbon and nutrient cycling was a major contributor to climate change over the Phanerozoic Eon.

We combine expertise across biogeochemistry, plant-symbiont physiology and computing to perform experiments that will inform our model of long-term terrestrial carbon and nutrient cycling. This will be the first continuous model of terrestrial biological processes over geological time and will allow us to directly test competing hypotheses regarding Earth’s floral and climatic history, providing new insights into the role of life in shaping climate.  

Plantfun diagram


Figure 1. Relationship between atmospheric CO2, surface temperature and the evolutionary history of plants. (A) Variations in CO2 and surface temperature. Reconstructed average surface temperature from de-trended oxygen isotopes (blue line), shown against geologic evidence for glacial periods and CO2 proxy estimates. (B) Land plant phylogeny. Plants for experiments (in green) have been carefully selected for which there is either very little or complete absence of data regarding function of fungal and microbial symbionts and as representative of key clades spanning land plant-symbiont diversification.