The reactivity of dissolved and suspended particulate phosphorus pools decreases with distance downstream in the Yellow River

Abstract The Yellow River is a potentially important source of terrestrially derived phosphorus to the limited Bohai Sea. However, seasonal variation in concentrations, partitioning and bioavailability dissolved particulate along length are poorly constrained. Here, we measure suspended at 72 stations from estuary during rainy season 2020 dry 2021. Mean concentrations total phosphorus, reactive were higher than season. Analysis with sequential fractionation indicated that generally associated calcium carbonate dominated pool. content relative contribution iron-bound particles increased season, suggesting variations bioavailability. Reactivity pools decreased estuary, low export potential bioavailable