DECADAL CHANGES AND SOURCES ANALYSIS OF MICROBIAL BIOMARKER GDGTS IN THE EAST CHINA SEA SEDIMENTS

The Glycerol Dialkyl Glycerol Tetraethers (GDGTs) is a group of newly discovered microbial biomarkers. The proxies based on GDGTs have become important indicators for revealing the sources of sedimentary organic matters and reconstruction of paleotemperature. In this study, we analyzed the content of the total organic matters and the fluxes of GDGTs in the core sediments from the DH5-1 station (29°28.118'N、123°06.639'E,water depth 63.5 m) located at the shelf area. The changes of organic matter sources were reconstructed using δ¹³C,C/N and BIT indexes during the past about 150 years. The results indicated that the enhanced East Asian winter monsoon in the past century strengthened the transport of terrestrial material from the Yangtze River Estuary to the shelf area. However, since the 1980s, increased human activities caused more nutrients influx which elevated marine production and reduced the relative percentage of terrestrial organic matters in the sediments.