There is a growing appreciation for how evolutionary responses to environmental change can alter vital ecosystem attributes. This project aims to study how evolutionary responses of an ecologically dominant plant to elevated atmospheric carbon dioxide concentration and nitrogen enrichment influence the flow of carbon into and out of coastal marsh ecosystems. The researchers plan to leverage a long-term experiment to characterize how plant traits that impact photosynthesis, the decomposition of organic matter in marsh sediments, and sediment accretion shift in response to increased carbon dioxide and nitrogen availability. They then plan to establish the underlying genetic basis for these traits, so that changes in genetic variation can be used to confirm that evolution has taken place. And finally, the researchers plan to quantify the consequences of changes in traits, and their associated genetic variation, for long-term carbon storage in, or loss from, highly productive marsh ecosystems. This would enable the researchers to identify mechanistic and functional links between plant evolution and carbon cycling in coastal marshes, which face an uncertain future due to anticipated sea-level rise. Findings from this research have the potential to improve our understanding of the global carbon budget, and to foster more effective coastal restoration by advancing our understanding of marsh persistence. Furthermore, the project can strengthen research infrastructure, create new educational and outreach opportunities, including the engagement of citizen scientists, and facilitate undergraduate research by students from groups underrepresented in science.
This project employs a complementary set of studies explicitly designed to bridge evolutionary biology and ecosystem ecology. Using a combination of new experiments and tissue archives from an ongoing, long-term global change experiment, the researchers plan to simultaneously assay in situ genetic and genomic variation using ddRAD-generated SNPs, to characterize functional trait (e.g. maximum rates of photosynthesis, stomatal conductance, and water use efficiency) variation in the field, and to quantify complete marsh carbon budgets (e.g. quantifying NPP, gaseous C losses, litter decomposition rate, and belowground biomass and C accumulation). These measurements are set in the context of more than a decade of exposure to elevated CO2 and nitrogen enrichment. To go beyond establishing associations between traits, genetic variation, and carbon flux post hoc, the researchers plan to conduct a complementary de novo quantitative genetics study of trait variation and physiology, with the intent of linking both to carbon fluxes mediated by individual plants. Establishing such mechanistic links can improve parameterization of a mechanistic model of C cycling in coastal marshes, enabling a more thorough characterization of ecosystem-level consequences of organismal evolution. Findings from this project can illustrate whether organismal evolution is an important determinant of how ecosystems function and offer new insights about how global change can directly and indirectly alter ecosystems.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
