Storm-induced sediment resuspension in the Changjiang River Estuary leads to alleviation of phosphorus limitation

Abstract

This paper presents an incubation experiment with sediment cores from the Changjiang Estuary Mud Area (CEMA) to quantify the release of nutrients due to simulated resuspension. The results show that except for nitrate (NO3−-N), phosphate (PO43−-P), ammonium (NH4+-N), nitrite (NO2−-N) and silicate (SiO32−-Si) were released from the sediment to the overlying water, primarily due to desorption (P), dissolution (SiO32−-Si) and mineralization (NH4+-N) with only minor direct contributions from the sediment pore water. The significant release of nutrients by resuspension and subsequent processes can alleviate the phosphorus and silicon limitation in water bodies, enhance the growth of phytoplankton, and thus promote the oxygen consumption and ultimately lead to hypoxia. The results of this study are highly relevant for many coastal areas in other parts of the world with large amounts of stored organic matter and nutrients in sediments and frequent perturbation by storm events.