Coupled Ecological-Geomorphological Response of Coastal Wetlands to Environmental Change

Duke University, Durham NC

Investigators

Abstract

Coastal wetlands are connected with an entire chain of geomorphic systems, from the sediment- and runoff- generating areas in the continental interior, to piedmont and floodplain areas, to the marine systems near the coast. As a result, coastal wetland dynamics are strongly coupled with a wide variety of Earth's surface systems and respond to a wide range of environmental changes taking place in apparently remote and unconnected areas. In fact, coastal wetlands are sensitive to changes in a large number of forcings, including fluvial sediment delivery rates, rates of sea level rise, subsidence rates, wave climate, and, via organic sediment production by plants, to changes in nutrient concentrations, temperature, and atmospheric CO2 concentration. Furthermore, only recently have the carbon storage and the rate of carbon burial per unit area been quantified in coastal wetlands, to find that they are the highest of any biome and thus major players in the global carbon cycle. Despite their sensitivity to environmental change and their importance in the global Earth system, a predictive understanding of wetland dynamics coupled with vegetation, the tidal channel network, the tidal flats, and the permanently submerged areas is still missing. This project will impact research, education, and society. Given the ecosystem services of threatened wetlands, and the large human population near the coast that will be affected by changes in wetland area, the results of the proposed work are of clear societal importance. The results will provide simultaneous estimates of changes in coastal geomorphology, ecosystem patterns, and carbon burial rates. Students at multiple levels (undergraduate, professional master, PhD) will be impacted by the project's education/outreach plans, which include new and enhanced coursework, and field experiences. The impact of the project will be enhanced through: 1) a substantial partnership with the Museum of Life and Science (Durham, NC), to increase the awareness of environmental change, targeting K-12 and the general adult audiences including those at the coast with hands-on activities, curricular material, and a documentary; and 2) a partnership with the Venice Lagoon ferry service Alilaguna, to disseminate project background and findings to anyone interested in the Venice Lagoon and its future. The intellectual merit of the project lies in developing, testing, and making available new remote sensing methods to observe coastal geomorphological and ecological patterns, from the single wetland scale to the sub-regional scale, in an improved understanding of the relative importance of different modes of environmental change for wetland survival, clarifying whether (or under what circumstances) coastal system response to changing forcing is likely to be gradual versus sudden. The project will generate and compare scenarios of coastal responses to expected environmental changes for two systems—one representative of wetland areas in the US eastern seaboard (North Inlet, SC), and one typical Mediterranean lagoon (Venice, Italy)—with implications for coastal zones globally, with particular attention to changes in rates of carbon burial and the carbon cycle. 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.