Enhancement of phosphorus storage capacity of sediments by coastal wetland restoration, Yellow River Delta, China

摘要

Un-restored (R-0) and restored (in 2006 (R-2006) and in 2002, (R-2002)) coastal wetlands were selected to study phosphorus (P) storage capacity and the risk of P loss in the Yellow River Delta (YRD). The results showed that the maximum P sorption capacity (Q(max)) in the wetland sediments varied between 201.8-1168.6 mg kg(-1); the average value was 576.2 mg kg(-1). Q(max) increased with increasing time since restoration (R-2002 > R-2006 > R-0). The eutrophication risk index (ERI) ranged between 0.27-2.07% and decreased with increasing time since restoration, but the relationship was not statistically significant (P > 0.05). A correlation analysis demonstrated that Fe-ox, Mg, and Al-ox are the main P sorption agents in wetland sediments, whereas TOC, pH, and clay particles have an important effect on P sorption and release. The analysis suggests that we should restore degraded coastal wetlands to help reduce the P load to offshore waters.