Chapter 5: The Biogeochemical Cycles

The Carbon-Silicate Cycle
• The cycling of carbon intimately involved with the
cycling of silicon.
• Weak carbonic acid falls as rain and weathers
silicate rich rocks
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– Releases Ca2+ and HCO3 – Silicon is transferred to oceans and used by marine
animals to construct shells along with the carbonates
– Shells deposited on sea floor become part of
sedimentary rock layer and return to Earth’s mantle in
subduction zones where volcanic eruptions may
eventually lead to the release of CO2 from superheated
rocks