Salt marshes protect coastal communities from flooding events, regulate water quality, and serve as nursery grounds that maintain fisheries. Environmental changes can have a significant impact on salt marsh ecology. This project will examine the synergistic effects of two environmental changes on salt marsh ecology - increases in atmospheric CO2 and rising sea levels. The impacts of increases in atmospheric CO2 will be assessed by studying evolutionary responses of salt marsh plant growth patterns. The impacts of rising sea level will be examined by testing whether such changes in marsh plant growth patterns result in in marsh stabilization by elevating the sediment surface of the marsh, and in turn maintaining marsh ecosystem function. Understanding these relationships may aid in effective coastal management and enable society to better anticipate and manage socioeconomic consequences of environmental change. Undergraduate and graduate students at two universities will be directly involved in the design and implementation of experimental work in the project. The project also will make findings from the work accessible to coastal managers and the public.
This research project will assess the role that genetically-based changes in a key salt marsh plant, Schoenoplectus americanus, has played in marsh persistence over a 100-year period. Genotypes spanning the last century will be retrieved from dormant seeds buried in sediments. The project will determine differences in plant traits, including growth rates and tissue allocation, across cohorts of "resurrected" genotypes using field, laboratory, and classroom-based experiments. The project will then incorporate results into the Marsh Ecosystem Model (MEM), to project the impact of changes in plant performance over the last century on the stability and persistence of salt marsh ecosystems. Broader societal impacts from this study will include a rare assessment of the contribution that evolutionary responses make to the function of a highly valued ecosystem. Because the societal benefits of salt marshes can be strengthened or weakened by environmental changes on decadal and centennial scales, it is important to determine the extent to which evolution of biological traits can amplify or dampen the likelihood of ecosystem persistence. The project will facilitate access to the Marsh Ecosystem Model (MEM) to researchers and managers via the PEcAn platform.
