Global patterns of dissolved silica export to the coastal zone: Results from a spatially explicit global model

We present a multiple linear regression model developed for describing global river export of dissolved SiO 2 (DSi) to coastal zones. The model, with river basin spatial scale and an annual temporal scale, is based on four variables with a significant influence on DSi yields (soil bulk density, precipitation, slope, and area with volcanic lithology) for the predam situation. Cross validation showed that the model is robust with respect to the selected model variables and coefficients. The calculated global river export of DSi is 380 Tg a −1 (340–427 Tg a −1 ). Most of the DSi is exported by global rivers to the coastal zone of the Atlantic Ocean (41%), Pacific Ocean (36%), and Indian Ocean (14%). South America and Asia are the largest contributors (25% and 23%, respectively). DSi retention in reservoirs in global river basins may amount to 18–19%.