Carbon cycle decomposition, fossil fuel

Some of the carbon released by decomposition may be washed into rivers and the ocean. Some of it may be taken up by other living things for use in their life processes. Some of it maybe buried in sediments and, over long periods of time, converted to fossil fuels. The burial and conversion of carbon compounds to fossil fuels upsets the balance between photosynthesis and respiration because these processes remove the carbon from the cycle for such long periods of time. Some carbon is also removed from the cycle for longs periods of time when the shells of some small ocean-dwelling... 

The carbon cycle in seas involves the assimilation of carbon dioxide dissolved in sea water by the phytoplankton with a simultaneous oxygen release. Zooplankton and fish use this oxygen for the respiration. During the organic matter decomposition, CO2 is supplied into the atmosphere. On land, the exchange of carbon dioxide with the atmosphere is accomplished by respiration, photosynthesis and by the combustion of fossil fuels. 

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