Carbon moves through biological, oceanic, atmospheric and geological reservoirs.
Key knowledge
Carbon cycles among the atmosphere, organisms, soils, oceans and rocks. Biological processes such as photosynthesis, respiration and decomposition exchange carbon, while weathering, sediment formation and tectonic processes participate in slower geological transfers.
Conditions and scope
The fast/slow distinction describes contrasting processes and time scales, not two isolated systems.
A natural cycle does not imply that emissions are automatically balanced or that reservoir amounts remain unchanged.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
NASA's documented fast/slow carbon-cycle account; no global flux values or local carbon budget are reproduced.
2026-10-10 · English reservoir and process scope checked against The Carbon Cycle; dated numerical rates and projections are excluded.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Agreement within this scope
Biological reservoirs, respiration/photosynthesis and geological transfers.
Fast biological exchanges and slow geological transfers connect.
Metabolism includes chemical pathways that break down substances and build biological materials. Catabolic pathways break complex molecules into simpler ones, often releasing usable energy; anabolic pathways build complex molecules and require energy input. Enzymes catalyse many of these reactions.
Carbon cycles among the atmosphere, organisms, soils, oceans and rocks. Biological processes such as photosynthesis, respiration and decomposition exchange carbon, while weathering, sediment formation and tectonic processes participate in slower geological transfers.
Photosynthesis, respiration and decomposition transfer carbon through biological processes.
Carbon cycles among the atmosphere, organisms, soils, oceans and rocks. Biological processes such as photosynthesis, respiration and decomposition exchange carbon, while weathering, sediment formation and tectonic processes participate in slower geological transfers.
Greenhouse gases absorb and emit thermal infrared radiation. This affects outgoing heat loss and allows Earth's surface and lower atmosphere to be warmer than they would be without those gases under comparable solar input.
Atmospheric carbon dioxide links carbon reservoirs with the greenhouse mechanism; not all carbon is atmospheric gas.
Oxygenic photosynthesis supplied oxygen while chemical reactions with reduced material consumed it. Atmospheric accumulation depended on production, consumption and burial rather than oxygen production alone. Geological redox evidence constrains changing conditions through Earth's history; oxygenation was not one instantaneous switch to the modern atmosphere.
Production and burial couple carbon and oxygen budgets.
The Calvin–Benson cycle carboxylates ribulose-1,5-bisphosphate through RuBisCO, reduces the resulting carbon compounds using ATP and NADPH, and regenerates the acceptor. In the standard accounting, fixing three CO₂ gives one net triose-phosphate equivalent while consuming nine ATP and six NADPH.
Carbon fixation transfers inorganic carbon into organic pools.
Nitrogen fixation converts N₂ toward biologically usable reduced nitrogen; ammonification, nitrification and denitrification transform nitrogen among distinct chemical pools. Phosphorus cycles through weathering, uptake, decomposition and sediment processes without a comparable dominant atmospheric gas pool. Rates depend on organisms, redox state and environmental exchange.
Different element cycles connect through organic material and ecosystem exchange.
Dissolved inorganic carbon includes aqueous CO₂/carbonic-acid convention, bicarbonate and carbonate. Adding CO₂ under stated conditions can shift carbonate equilibria, increase hydrogen-ion activity and reduce carbonate availability. Air–sea exchange, biology and mixing also affect the observed carbon system.
Ocean species and exchange contribute to carbon reservoirs.