Organic carbon atmospheric input

Most of the carbon taken up or lost by terrestrial ecosystems and the ocean is exchanged with the atmosphere, but a small flux of carbon from land to the ocean bypasses the atmosphere. The river input of inorganic carbon to the oceans (0.4 PgC yr ) is almost balanced in steady state by a loss of carbon to carbonate sediments (0.2 Pg C yr ) and a release of CO2 to the atmosphere (0.1 Pg C yr ) (Sarmiento and Sundquist, 1992). The riverine flux of organic carbon is 0.3-0.5 PgC yr , and thus, the total flux from land to sea is 0.4-0.7 PgCyr ... 

The quantities of carbon stored in the form of atmospheric carbon dioxide, CO2 in the hydrosphere and carbonates in the terrestrial environment, substantially exceed those of fossil fuels. In spite of this, the industrial use of carbon dioxide as a source of chemical carbon is presently limited to preparation of urea and certain carboxylic acids as well as organic carbonates and polycarbonates. However, the situation is expected to change in the future, if effective catalytic systems allowing to activate carbon dioxide will become available. In this connection, the electrochemical reduction of CO2, requiring only an additional input of water and electrical energy, appears as an attractive possibility. 

In addition, the present-day burial rate of organic carbon in the ocean may be about double that of the late Holocene flux, supported by increased fluxes of organic carbon to the ocean via rivers and ground-water flows and increased in situ new primary production supported by increased inputs of inorganic N and P from land and of N deposited from the atmosphere. The organic carbon flux into sediments may constitute a sink of anthropogenic CO2 and a minor negative feedback on accumulation of CO2 in the atmosphere. 

Any factor(s) that alters the level of primary production in natural and managed ecosystems will affect the dynamics of organic carbon and phosphorus in soil. This includes changes in inputs of major plant nutrients (including phosphorus) in the form of mineral fertilizers and manure, as well as inputs of nitrogen and sulphur from atmospheric pollution. In addition, predicted... 

---