Global Effects of Ozone Depletion Essay -- Environment Ozone Layer Ess

Global Effects of Ozone Depletion Ozone depletion in the earth’s atmosphere is under constant scrutiny by the American press and people. Perhaps the concern is warranted; the ozone layer protects life on earth by absorbing 97-99% of the damaging ultraviolet radiation from the sun (U.S. Environmental Protection Agency, 2006). Over the past twenty years, the stratospheric ozone has decreased approximately 3% per decade. Possible concerns have been raised about loss of polar caps, DNA damage, increased human health risks, and environmental process disturbance. Emerging research has helped clarify effects of global ozone depletion. Three areas that have received recent scientific attention include UV effects upon macroalgae, decomposition, and nitrogen fixation. Ozone is depleted both by natural and industrial sources. One natural source of depletion is volatile organohalogens, which are produced by marine macroalgae (Laturnus, et. al., 2004). Scientists are not sure why macroalgae produce organohalogens, but many believe it is due to stress. UV radiation is a known source of plant stress. If this is the case, then plants would likely produce more organohalogens if exposed to increased UV radiation. To test this hypothesis, a group of Swedish scientists applied increased levels of radiation to five marine macroalgal species. After four hours, the levels of organohalogens produced by the macroalgae were measured. The scientists found that â€Å"exposure to ultraviolet radiation rendered a significant increase in the concentration of four or more of the volatile organohalogens for each of the studied macroalgal species† (Laturnus, et. al., 2004). Although the findings appear quite disturbing initially, the inc... ...a A.; Sala, Osvaldo E.; Robson, T. Matthew; Caldwell, Martyn M.; Scopel, Ana L. 2005. Direct and indirect effects of solar ultraviolet-B radiation on long-term decomposition. Global Change Biology 11:1982–1989. Solheim, Bjorn; Zielke, Matthias; Bjerke, Jarle W.; Rozema, Jelte. 2004. Effects of enhanced UV-B radiation on nitrogen fixation in arctic ecosystems. Plant Ecology 182:109–118. U.S. Environmental Protection Agency. 2006. Ozone. http://www.epa.gov/maia/-html/ozone.html Wikipedia Encyclopedia. 2006. Ozone Depletion. http://en.wikipedia.org/wiki/-Ozone_depletion Yang, Eun-Su; Cunnold, Derek M.; Salawitch, Ross J.; McCormick, M. Patrick; Russell, James III; Zawodny, Joseph M.; Oltmans, Samuel; Newchurch, Michael J. 2006. Attribution of recovery in lower-stratospheric ozone. Journal of Geophysical Research-Atmospheres, 111 (D17): Art. No. D17309.