ACCUMULATION OF CARBON AND NUTRIENTS IN COASTAL WETLAND IN THE YELLOW RIVER DELTA
DING Xi-Gui;YE Si-Yuan;ZHAO Guang-Ming;YUAN Hong-Ming;WANG Jin;Key Laboratory of Coastal Wetland Biogeosciences,China Geologic Survey; Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology,Ministry of Land and Resources; Qingdao Institute of Marine Geology;
Core ZK1 in a shallow depth of 24.6m was drilled in the Yellow River Delta in 2007, from which sediments were sampled for detailed sedimentological observations and analyses for water content, organic carbon(Corg), total carbon(TC), and nutrient compositions. Stratigraphic analysis recognized seven sedimentary environments, and the evolution of coastal wetland was revealed by chronological dating by AMS 14C. Sedimentation rate and carbon accumulation rate were calculated, and historic records of the Yellow River diversions was established. Results show that TC, Corg, and nutrients(except for element S) are in good linear correlations(R20.7, P0.05); the accumulation rates of Corg, TC, N, and P have very significant positive correlations with sedimentation rates(R20.95, P0.01). The sedimentation rates were the main factor controlling the accumulations of Corg, TC, N, and P. Although the Corg concentration is low(1%) in modern Yellow River Delta sediments, the average accumulation rate of Corg in the core sediment is very high at 648.1g/(m2·a) due to high sedimentation rate, which is much higher than those in other high-Corg wetlands in the world. Thus, the modern Yellow River Delta is a large carbon sink due to its high sedimentation rates.