Program

Increasing anthropogenic nutrient loading has lead to eutrophication, harmful algal bloom, hypoxia in coast waters worldwide. Climate change is likely to increase the occurrence and intensity of heavy storms. Storm-driven pulse input of riverine nutrients and effects on coastal ecosystems is poorly understood. Here we show that storm runoff export more inorganic nutrient (ammmonium and phosphate) which might stimulate algal bloom in lower estury. Synchronous observations along the river-estuary-bay (Southeast China) were performed during three flood periods in 2013-2014. Changes in nutrient concentration and composition in coastal water mainly depend on rainfall (size, timing, location). Ammonium and phophate derived from storm runoff were likely to stimuate algal bloom based on their removal behavior observed in the lower estury accompanied with high Chl-a. Discrepancy in nutrient fluxes passing through the River-Estuary interface and the Estuary-Coast interface suggests that estuary exerts as a regulator of seaward nutrient export. Current findings provide important references to develop a sound predictive model for early warning of algal bloom. This study highlight an integrated understanding of watershed processes of nutrient input and coastal biogeochemical response to storm events.