Release and Microbial Degradation of Dissolved Organic Carbon and Nitrogen from Phragmites australis and Suaeda salsa in the Wetland of the Yellow River Estuary

摘要

Release of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) from two dominant plants Phragmites australis and Suaeda salsa in the Yellow River Estuarine wetlands was studied in laboratory incubation experiments. The release dynamic of dissolved organic carbon (DOC), dissolved nitrogen (DN) and CDOM from the plants was rapid process and hydrolysis played an important role in the initial leaching stage of the organic compounds from the plants. Bacterial activities enhanced the release processes of DOM during degradation of the plants and utilization of the released organic compounds. The fluorescence characteristics of the CDOM indicate that the protein- like organic substances are the major components released from P. australis and S. salsa in the initial stage and these compounds are labile and highly biodegradable. Our study suggests that leaching of DOM from P. australis and S. salsa provide not only major sources of DOC, DN, and CDOM that affect many biogeochemical processes, but also as important food sources supporting microbial communities in the Yellow River wetlands and adjacent coastal waters.