Deciphering Core Records of Carbon and Nitrogen in Typha-Dominated Freshwater Wetlands

I conducted decomposition experiments and examined soil characteristics in restored and natural freshwater marsh platform sites to decipher core records of soil C and N. Carbon loss rates and changes in ẟ13C and ẟ15N were obtained from decomposition experiments. Core samples at each site were analyzed for bulk density, weight %C, %N, ẟ13C, and ẟ15N. Typha C loss rates were similar among sites, and there was little change in ẟ13C composition, suggesting that DOC leaching is significant. Core carbon storage is higher in natural wetland sites. Initial Typha %N and ẟ15N reflect local N concentrations and sources to each wetland. ẟ15N increases between decomposed vegetation and upper cores in the tidal wetlands, possibly indicating denitrification. In N-rich wetlands, core %N and ẟ15N reflect differences in N sources and changes in N sources over time. In a wetland limited by N transport, core %N and ẟ15N may reflect vegetation N uptake