2.2 Nutrition & Energy Flow Bio-geo-chemical cycles Carbon Cycle

The Carbon Cycle

Carbon Cycle

Living things are made of carbon. About 50% of the dry weight of both plants and animals on earth is carbon.

Presence in human body (%) Name of chemical element Presence 65Oxygenin all liquids and tissues, bones, proteins 18Carboneverywhere 10Hydrogenin all liquids and tissues, bones, proteins 3Nitrogenin all liquids and tissues, proteins 1.5Calciumlungs, kidney, liver, thyroid, brain, muscles, heart, bones 1Phosphorusurine, bones 0.35Potassiumenzymes 0.25Sulphurproteins 0.15Sodiumin all liquids and tissues (in terms of salt) 0.05Magnesiumlungs, kidney, liver, thyroid, brain, muscles, heart tracesFluorinebones, teeth tracesChlorinein body liquid tracesManganeseenzymes tracesIronenzymes

Carbon Cycle The element carbon has the ability to cycle globally, due to its atmospheric reservoir. In the Carbon Cycle, carbon dioxide (CO 2 ) from the atmosphere is absorbed by plants through photosynthesis, then returned to the atmosphere through cellular respiration.

Carbon Cycle The carbon dioxide in the atmospheric reservoir is taken in by plants in order to complete photosynthesis. During photosynthesis, plants take in CO 2 and H 2 O then with the energy from the sun they convert this into C 6 H 12 O 6.

Carbon Cycle The plants then serve two purposes: they become food for primary consumers and they produce oxygen (O 2 ) as a byproduct. The oxygen in the air is taken in by all organisms (including plants) as part of cellular respiration, which returns carbon dioxide to the atmosphere.

Carbon Cycle The food from plants that is eaten by the primary consumers contains carbon, which is passed up through the trophic pyramid to all levels of consumers. C 6 H 12 O 6. is glucose, or the food that the plant makes for itself. As you can see from the formula for glucose, in addition to carbon, it contains hydrogen and oxygen.

Carbon Cycle Dead material contains carbon and is decomposed and eaten by decomposers, another part of the food chain.

Carbon Cycle A big problem we have going on right now is the extra emission of carbon dioxide from the burning of fossil fuels in factories, automobiles, etc. Fossil fuels were originally stored or sequestered carbon. They were not meant to be part of the current carbon cycle. Burning fossil fuels increases the level of CO 2 in the atmosphere, thus throwing the entire cycle off balance.

Carbon Cycle Abiotic reservoirs of carbon: atmosphere, soil Biotic reservoirs of carbon: plants, animals, decomposers

Carbon Cycle When an organism dies and decomposes carbon, water (hydrogen & oxygen), and nitrogen are released back into the atmosphere.

Carbon Cycle Carbon dioxide in the atmosphere enters the biotic parts of the biosphere through ___. a.burning of forests b.photosynthesis c.combustion of fossil fuels d.all of these

one Pg [petagram]=one billion metric tonnes=1000 x one billion kg