Carbon cycle
Ecology · Botany · Marine Biology
Say it: KAR-bun SY-kul
The carbon cycle is the movement of carbon among the air, oceans, living things, soils and rocks through processes like photosynthesis and respiration.
Definition
What is the carbon cycle?
The carbon cycle is the continuous exchange of carbon among Earth's main reservoirs: the atmosphere, where it is mostly carbon dioxide; the oceans, which hold about 50 times more carbon than the air; living organisms and soils; and rocks and sediments, including limestone and fossil fuels, which store by far the largest amount. Carbon forms the backbone of every organic molecule, so its cycling links all life on the planet.
The cycle has a fast biological part and a slow geological part. In the fast part, plants, algae and other autotrophs take in carbon dioxide during photosynthesis and build it into sugars, and producers, consumers and decomposers release it again through cellular respiration and decay. In the slow part, carbon dioxide dissolves in seawater to form bicarbonate, which marine organisms use to build calcium carbonate shells that settle and, over millions of years, become limestone. Buried remains can turn into coal, oil and gas, and volcanoes return carbon to the air.
Since the Industrial Revolution, people have released carbon stored over millions of years by burning fossil fuels, clearing forests and making cement, raising atmospheric carbon dioxide and warming the climate. The ocean absorbs much of the extra gas, which lowers its pH in a process called ocean acidification.
Word parts
Where does the term “carbon cycle” come from?
- carbon
- coal, charcoalLatin carbo, via French carbone
- cycle
- circleGreek kyklos
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Terms that go with it
- PhotosynthesisPhotosynthesis is the process in which plants, algae and cyanobacteria capture light energy and store it in sugar built from carbon dioxide and water.
- Nitrogen cycleThe nitrogen cycle is the set of mainly microbial processes that move nitrogen between atmospheric gas, ammonium, nitrate and living organisms.
- DecomposerA decomposer is an organism, mainly a bacterium or fungus, that breaks down dead organisms and wastes and returns their nutrients to the environment.
- EcosystemAn ecosystem is a community of living organisms together with the nonliving environment they interact with, linked by energy flow and nutrient cycling.
- PlanktonPlankton are organisms that drift in oceans, lakes and rivers because they cannot swim against currents, from microscopic algae to large jellyfish.
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Checked against
Written for biofideX in plain words, after checking these references:
- OpenStax Biology 2e, 46.3 Biogeochemical Cycles
- NOAA Education: Carbon cycle
- American Heritage Dictionary: carbon
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