Linking Impacts of Climate Change to Carbon and Phosphorus Dynamics Along a Salinity Gradient in Tidal MarshesEPA Grant Number: R832222
Title: Linking Impacts of Climate Change to Carbon and Phosphorus Dynamics Along a Salinity Gradient in Tidal Marshes
Investigators: Vile, Melanie A. , Neubauer, Scott C. , Velinsky, D. J.
Current Investigators: Vile, Melanie A. , Neubauer, Scott C. , Weston, Nathaniel
Institution: Villanova University , Academy of Natural Sciences
Current Institution: Villanova University , University of South Carolina at Columbia
EPA Project Officer: Hunt, Sherri
Project Period: April 14, 2005 through April 13, 2008 (Extended to April 13, 2010)
Project Amount: $705,211
RFA: Effects of Climate Change on Ecosystem Services Provided by Coral Reefs and Tidal Marshes (2004) RFA Text | Recipients Lists
Research Category: Ecosystems , Climate Change , Water , Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration , Global Climate Change , Water and Watersheds
Tidal freshwater marshes are often located in areas experiencing intense urbanization pressure, yet they provide valuable services to coastal ecosystems by acting as water quality filters (removing nutrients and sediments), sequestering carbon [C] and phosphorus [P], serving as nursery habitat for fishes, and buffering storm and flood waters. A climate change stressor that is unique to tidal freshwater systems is the intrusion of salt water into environments that have historically been dominated by freshwater flows. We are especially interested in how the increase in SO42- concentration associated with salt water intrusion will affect the biogeochemical interactions that govern the cycling of C and P in tidal freshwater marshes and affect fluxes of elements between marshes, tidal waters, and the atmosphere.
We will implement a novel, three-phase approach to determine changes in tidal marsh metabolism [e.g., CO2 and CH4 gas fluxes and SO42- reduction], C and P sequestration [sediment deposition and burial], sediment P speciation, and porewater chemistry at sites along a low-salinity transitional gradient in the Delaware Estuary. Phase 1 consists of field observations [as a space-for-time substitute] to assess current ecosystem services provided by tidal freshwater and low salinity marshes, and allow us to predict how these services may change as a result of salt water intrusion. Phases 2 and 3 provide a more detailed look at specific biogeochemical processes that impact cycling of C, P, and S. In Phase 2, we will conduct laboratory experiments using marsh cores exposed to low salinity levels [< 5 psu] to study the short-term [weeks to months] impact of increased salinity on marsh sediment C and P biogeochemistry. Phase 3 involves large-scale manipulations in the field [reciprocal transplanting of cores between tidal freshwater, oligohaline, and mesohaline marshes] to examine longer-term ~1-2 yr, ecosystem-level responses of marshes to elevated salinity.
This research will improve the assessment of how ecosystem services provided by tidal freshwater marshes are likely to respond to predicted changes in climate-induced sea level rise and salinity. We expect that a small increase in salinity in tidal freshwater wetland sediments will increase rates of decomposition [but decrease rates of C burial and emissions of the greenhouse gas CH4], and cause a release of sediment-bound P from the soils. The results from this project can be used to improve existing climate change forecast models and will allow appropriate management to moderate the impacts of future climate change in low salinity tidal marshes.