Carbon

Without the special properties of carbon, life - as we know it - would not be possible on Earth.

The element carbon (abbreviation C) occurs in its inorganic form (IC = inorganic carbon) in the aquarium as gaseous carbon dioxide (CO₂) or dissolved as carbonic acid (H₂CO₃), hydrogen carbonate (HCO₃) and carbonate (CO₃). Solid salts are mostly forms of calcium carbonate CaCO₃ - abundantly present as coral skeletons or their deposits in the form of living stones and coral rubble, furthermore as mussel shells, foraminifera and many others.

Organic carbon (OC) occurs in more than 10 million known compounds, so that only dissolved organic carbon (DOC) and particulate organic carbon (POC) need to be mentioned here as a simplification. They are combined to form total carbon (TC). Almost everything in the aquarium - except water and some dissolved salts - contains carbon.