Carbon Dynamics in Response to a Shifting Terrestrial Aquatic Interface in Coastal Plain Wetlandscapes

Authors

Matthew J. Cohen¹* ([email protected]), Katie Glodzik¹, Josh Epstein¹, Sunita Shrestha¹, Samantha Howley¹, Esther Lee¹, Alexis Jackson², James Jawitz³, Daniel McLaughin⁴, Stefan Gerber³, Nicholas Ward⁵, David Lewis⁶, Faith Hale⁶, Amanda Subalusky⁷, Chris Dutton⁷

Institutions

¹School of Forest, Fisheries and Geomatics Sciences, University of Florida, Gainesville, FL; ² Environmental Engineering Sciences, University of Florida, Gainesville, FL; ³ Soil, Water and Ecosystem Sciences, University of Florida, Gainesville, FL; ⁴ Forest Resources and Environmental Conservation, Virginia Tech University, Blacksburg, VA; ⁵ Pacific Northwest National Laboratory, Sequim, WA; ⁶ Department of Integrative Biology, University of South Florida, Tampa, FL; ⁷ Department of Biology, University of Florida, Gainesville, FL

Abstract

Water table variation in low-relief landscapes creates a dynamic terrestrial-aquatic interface (TAI), the ebb and flow of which controls reactions that stabilize or remineralize organic matter. Geomorphic heterogeneity in wetland depressions creates functional variation in water storage and connectivity over space to complement the temporal variation intrinsic to seasonal hydrometeorological forcing. Researchers seek to understand how landscape-scale variation in hydrology and topography, and by extension the shifting position and length of the TAI, regulate the storage and export of carbon (C) via both vertical and lateral pathways. The early work on this project has been to concatenate digital terrain data, existing water level time series in wetlands and streams, and remote sensing of upland and wetland forest productivity to characterize (i.e., model) the extant variation in hydrological conditions in two hydrologically contrasting wetlandscapes in north Florida. Based on this variation, the team chose 12 wetlands and 10 streams to instrument for continuous and synoptic variation in water level, soil redox conditions, greenhouse gas production rates using low-cost telemetered environmental sensors. Researchers further initiated sampling to explore within-site variation in the quantity and quality of stored organic matter. The objective is to synthesize the hydrotopographic controls on C storage and release from these dynamic landscapes, and embed these functions more realistically in land surface models by structuring subgrid variation to reflect the changing extent of wetland and upland extent with a shifting TAI.