Analyzing and quantitatively evaluating the organic matter source at different ecologic zones of tidal salt marsh, North Jiangsu Province, China

In order to explore the effect of different eco-logical zones and their above plants in the organic matter cycling of the whole tidal salt marsh,indicators such as total organic carbon(TOC),total nitrogen(TN),C/N ratio,δ13C and d15N of surface,core sediments,and plants of tidal salt marshes in North Jiangsu Province are analyzed.Subse-quently,distribution regularities of these measurement indi-cators are discussed,and the biogeochemistry processes between sediments and plants are also analyzed.Lastly,the organic matter sources of different ecologic zones in tidal salt marsh are evaluated,and the organic matter accumu-lations in different ecologic zones induced by their plants are also compared.These results indicate that TOC,TN,C/N ratio and δ13C showed obvious zonal distribution.The organic matter sources are dominated by marine input in the silt flat,artemisia schrenkiana flat,and the transition zone between silt and spartina alterniflora flat,and are controlled by terrigenous input in spartina alterniflora flat.Spartina alterniflora plays an important role in the accumulation of organic matter in the whole tidal salt marshes ecosystem.In the study area,the annually increased TOC,organic matter and TN in the spartina alterniflora,artemisia schrenkiana and reed flats reach 6,451,12,043 and 536 t,respectively.The amount of TOC,organic matter and TN accumulated in the spartina alterniflora flat is more than that in other ecological zones,which shows that the spartina alterniflora flat exert a non-replaceable effect on the material cycle and exchange in the whole tidal salt marshes ecosystem.