Investigating the Effects of Urbanization and Restoration On Plant-Microbe Interactions in Tidal Freshwater Wetlands (Washington, D.C. and Maryland).

Underdeveloped and degraded soil properties in restored and urban wetlands negatively affect ecosystem functions, including carbon sequestration and nitrogen cycling.  Soil microorganisms are primarily responsible for these services and would be ideal targets to recover functions in anthropogenically-disturbed ecosystems.  Because current wetland assessment goals are focused on shaping plant community to achieve services, we must have a better fundamental understanding of how these communities shape microbial diversity and their associated functions. In August 2012, three restored and two natural reference wetlands in the Anacostia and Patuxent River watershed were selected to investigate plant-microbe interactions. Soil samples were collected from the root zone of Typha latifolia (Cattail), Phragmites australis (Common Reed), Peltandra virginica (Green Arrow Arum), and Lythrum salicaria (Purple Loosestrife).  Our analysis corroborates that soil organic matter is reduced in urbanized and restored wetland sediments.  Additionally, plant species richness was less diverse in restored sites compared to natural sites in both watersheds. Bacterial and archaeal composition in urban affected watershed were more similar to restored wetlands than the natural reference wetland located in the sub-urban site. While soil chemistry did not reflect signature associations with plant type, we expect our sequence and functional gene analysis will reveal unique signatures since microorganisms are more responsive to slight changes in resources.  Results from this study will enhance our understanding of plant-microbe relationships and provide direction to successfully restore wetland ecosystem services.