Evidence of Incorporation of Abiotic S and N into Prairie Wetland Dissolved Organic Matter

Wetlands in the prairie pothole region of North America, which are among the most threatened ecosystems in the world, provide many services, ranging from waterfowl habitats to pesticide attenuation to carbon sequestration. The dissolved organic matter (DOM) that occurs within these wetlands, in surface waters and sediment porewaters, was examined by molecular-level techniques. While it contains components typical of DOM from surface and subsurface waters, both sulfidic and nitrogenous organic molecules are significantly more abundant in this DOM pool than in other natural waters and show distribution patterns that exactly mimic the pattern observed for DOM that is comprised of only carbon, hydrogen, and oxygen. This indicates that incorporation of N and S within DOM is abiotic and nonspecific, likely involving hydrogen sulfide, polysulfides, and N-containing nucleophiles.