Vol­ca­noes Make the Land Fer­tile

Science Illustrated - - NATURE/SUPERVOLCANOES -

Ma­jor vol­canic erup­tions cause acute chaos in the world, but without them, the planet would end up as a cold snow­ball. The erup­tions keep the car­bon cy­cle – Earth’s in­te­grated ther­mo­stat – go­ing.

Vol­ca­noes emit gaseous car­bon, CO , to the at­mos­phere. The car­bon diox­ide heats the world via its green­house gas qual­i­ties.

In a warm world, more rain will fall. The rain ab­sorbs CO , which com­bines with the wa­ter, pro­duc­ing car­bonic acid – H CO .

The acid rain­wa­ter dis­solves rock min­er­als. The car­bon is bound in bi­car­bon­ate ions – HCO .

Bi­car­bon­ate is a ba­sic build­ing block, when ma­rine or­gan­isms pro­duce shells of cal­cium – CaCO . The shells end up on the ocean floor.

Con­ti­nen­tal drift pulls the ocean floor into Earth's man­tle, where some of it melts, re­leas­ing CO , which forms part of magma. Fi­nally, the magma ends up in a vol­canic eruption.

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