Citation:

Watson, E., A. Oczkowski, K. Raper, A. Gray, C. Wigand, D. Velinsky, AND F. Rahman. Impacts of episodic storms on coastal wetland processes in the Northeastern U.S. American Geophysical Union (AGU) Fall Meeting, San Francisco, California, December 12 - 16, 2016.

Impact/Purpose:

This presentation will address how climate change, via episodic coastal storms, will impact coastal wetland processes.

Description:

Climate model simulations corresponding to IPCC emissions scenarios suggest that by 2100, increases in precipitation intensity, the number of heavy precipitation events, and the intensity of the wettest events are all expected to increase, while concurrently, one to three month droughts could occur as frequently as once per summer in the U.S. Northeast. Here, we report on a combination of field and mescosm experiments where we examined impacts of changing precipitation patterns on coastal wetland nitrogen retention and sediment deposition. We found that more even precipitation promoted higher rates of wetland nitrate retention than larger episodic events, suggesting that changing precipitation patterns are altering how coastal wetlands incept, retain, and transform nitrogen. In contrast with nitrogen retention, which is promoted by even precipitation receipt, event-based monitoring of sediment deposition suggests that episodic storms account for much of the sediment deposited in coastal wetlands. We found that tides only flooded the upper marsh to significant depths (>15cm) during storms. Using empirical data to parameterize a process-based marsh elevation simulation model, we found that increased storm frequency will likely increase the probability of marsh survival with sea level rise significantly, while increases in storm intensity will likely have negligible effects. Jointly, these results suggest that changes in storminess will significantly impact coastal wetland function and persistence.

Record Details: