Ecogeomorphological feedbacks in a tidal freshwater marsh
Abstract
Tidal freshwater marshes are critical components of fluvial and estuarine ecosystems. However, ecogeomorphological feedbacks (i.e., feedbacks between sediment dynamics and the vegetation community) in freshwater marshes have not received as much attention as within their saltwater counterparts. This study evaluates the role of these feedbacks in stabilizing marsh-surface elevation, relative to sea-level rise, in Dyke Marsh Preserve (Potomac River, USA). Specifically, we relate the composition of the vegetation community to current and historical patterns of sedimentation that occur on bimonthly to decadal time scales. Along with a ~3-year time series of bimonthly and seasonal-scale observations, 210Pb (half-life 22.3 y) profiles are used to identify sites with relatively steady sediment accumulation (i.e., stable sediments) and those with numerous deposition/erosion events (i.e., unstable sediments). Differences in the vegetation community (e.g., composition, stem density) and sediment character (e.g., organic content, grain size) among sites in each of these stability categories are examined with statistical techniques and compared to observations of marsh-surface elevation change. The resulting insights are placed into a geomorphological context to assess the potential response of this marsh to rapid global environmental change.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMEP23A..07P
- Keywords:
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- 0497 BIOGEOSCIENCES Wetlands;
- 0439 BIOGEOSCIENCES Ecosystems;
- structure and dynamics;
- 1641 GLOBAL CHANGE Sea level change;
- 1861 HYDROLOGY Sedimentation