Mountains erode, reefs form

Not only bacteria and algae love CO2 – mountains munch it!  However it doesn’t do them any good, they crumble from it. The atmospheric CO2 dissolves in rainwater as carbonic acid (H2CO3). This weak acid rain drops on the mountains, the mountain range erodes. Among other things limestone is formed, that in dissolved form is swept with the rivers to the sea.There it’s already expected.
Many ocean organisms use the calcium carbonate in the water and make their housings out of it. Reefs are repositories of CO2 built out of limestone (CaCO3).

Continents on collision course

The continents are underway. Some were torn apart in the course of time, others collided together during their journey – then mountains rose up.  From rainwater, CO2 and the rock of the mountains are formed clay, sand, and dissolved limestone, that are swept away with the water. In the oceans this dissolved limestone is precipitated out again by organisms. Thus calcium carbonate layers are formed on the ocean floor. These are pressed into the depths and heated. The stored CO2 is set free and gets into the atmosphere again through volcanoes. 


Chapter 4