Silicon Cycle

The silicon cycle is the biogeochemical pathway by which silicon moves between the solid Earth, soil, rivers, the ocean and living organisms: chemical weathering of silicate rock releases dissolved silica that rivers carry to the sea, where diatoms, radiolarians and sponges draw it out of the water to build their silica shells and skeletons, and much of that biologically fixed silicon eventually settles to the seafloor as siliceous ooze that lithifies into rock such as chert, closing the loop over geological time. Marine diatoms alone are estimated to cycle roughly as much silicon each year as all of the world rivers deliver to the ocean, making the biological step the dominant control on the modern marine cycle rather than a side process. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/