Carbon, Phosphorus and Nitrogen Cycles
Humans have a great impact on each of the Carbon, Phosphorus, and Nitrogen cycles in the Ecosystem.
The carbon cycle starts with the reservoir of the carbon dioxide in the air, the carbon atoms move from carbon dioxide through photosynthesis into atoms of organic molecules that form the plants body. These carbon atoms are then further metabolized and are eaten and turned into tissue that all organisms in the ecosystem use. Half of the atoms are respired by the plants and animals and half are deposited back into the soil in the form of dead animal and plant matter, which are eaten by decomposers and transformed back into carbon dioxide. Humans impact this cycle because we are removing so much of the photosynthetic efforts of the plants in order to support our enterprises, we are “diverting 40% of the photosynthetic productivity of land plants to support human enterprises,” (pg 67). Two examples of our harmful tendencies are burning fossil fuels which has increased atmospheric carbon dioxide “35% over preindustrial levels,” (pg. 67) and logging. These both are being used naturally by the ecosystem and the lack of these resources causes stress and strain to keep the balance. At the rate it is going carbon to complete its cycle from the atmosphere through one or more living organism and back to the atmosphere happens about every 6 years.
The phosphorus cycle includes the cycle of all the biologically important nutrients found in the natural minerals. These elements include iron, calcium, potassium found in the rock and soil minerals in the lithosphere. Over time a rock breaks down and releases phosphate (PO43-) and other ions which replenish phosphorus that is lost due to runoffs and leaching. The phosphate is absorbed by plants and turned into compounds that are moved through the food chain. Humans impact this cycle because we are using the phosphorus to make fertilizers, animal feeds, detergents or other products...
References: Wright, R. T., & Boorse, D. F. (2014). Environmental science (12th ed.) San Francisco, CA: Pearson Education, Inc.
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