Retention effects of river damming on dissolved silicon

The transport of river-borne dissolved and suspended substances to global oceans is significantly affected by dams. In most cases, dissolved silicon (DSi) is partly retained in reservoirs, thereby altering the community structure of phytoplankton downstream and even in their recipient estuaries. Reservoirs differ greatly in their ability to retain DSi. Factors controlling DSi retention in reservoirs have been studied for a specific reservoir or a set of reservoirs within a basin; however, the impact of trophic states, lithologic characteristics, and water exchange rates passing through reservoirs on DSi retention have not yet been compared and analyzed comprehensively across regional and continental scales. In this work, we compiled data from published literature and investigated the correlation between DSi retention efficiency and its potential controlling factors. We found that the average water depth and the hydraulic load (derived from the average water depth and the water residence time) of reservoirs were significantly and negatively correlated to DSi retention efficiency (<i>p</i> &lt; 0.05). The results can improve our understanding of the retention effects of river damming on DSi and provide valuable information for ecological management of river damming.