Carbon sequestration and its controlling factors in the temperate wetland communities along the Bohai Sea, China

Abstract

The carbon sequestration rate (CSR) in deltaic wetlands is associated with the nutrient balance, sediment (soil) accretion rate (SAR) and geological and climatic conditions. To explore the relationships between these factors, micronutrients; C, N, and P concentrations; and ages determined using either paleosols or radiometric dating with 210Pb were analysed from a total of 14 cores from the Yellow River delta (YRD) and Liaohe delta (LHD) wetlands, collected in 2007 and 2012 respectively. With the exception of Ca, concentrations of N, organic C, Cu, Zn, Fe, Mn, Mg, K, Al and H+ were significantly higher in the wetland soils of the LHD, but organic CSR was virtually identical at the two sites, ~140gCm–2year–1 at sites above mean sea level (MSL). SAR and organic CSR at LHD sites below MSL were ~2.8 times the corresponding rates at sites above MSL. SAR and total CSR were much higher in the YRD than LHD because of the much greater accumulation rate of CaCO3 in the YRD. Organic CSRs were primarily controlled by SAR in both deltaic wetland systems. However, organic CSRs were much more sensitive to changes in SARs in LHD wetlands than YRD wetlands.