- Last Updated on Wednesday, 12 February 2014 16:12
The (Ozone) hole above Antarctica has proven to have detrimental effects on living organisms and the food chain.
1. Human Health:
Ozone Depletion leads to humans suffering from excessive UV-B radiation exposure. Excessive UV-B radiation leads to more skin cancers and eye cataracts and loss of immunity to diseases. In plants it reduces productivity.
Skin cancer (melanoma and non-melanoma)-studies have suggested that sunscreen use may not be protective against melanoma and may even be associated with increased risk. Explanations offered for these observations are that wearing sunscreens, while reducing UV-B exposure, provides little protection from UV-A exposures and that such exposures are important to melanoma risk.
The melanoma form of skin cancer has the ability to spread quickly throughout the body and invade other cells.
2. Terrestrial Ecosystems (agriculture,plants):
Ozone depletion may also lead to a loss of plant species and reduce global food supply: Exposure to UV radiation may have a dramatic effect on terrestrial plant life as excessive UV radiation inhibits the growth processes of almost all green plants.
Plant stunting is also typically seen in UV-irradiated plants and, in general, UV radiation affects plant growth by reducing leaf size and limiting the area available for energy capture during photosynthesis.
Plants form the basis of the terrestrial food web, prevent soil erosion and water loss, and are the primary producers of oxygen and a primary removal sink for carbon dioxide, a greenhouse gas.
Indirect changes caused by UV radiation, - such as flowering and germination rates and changes in plant form and how nutrients are distributed within the plant - may be more important than the damaging effects of the radiation itself.
3. Effects on Aquatic Ecosystems
Phytoplankton forms the foundation of aquatic food webs. Phytoplankton productivity is limited to the euphotic zone, the upper layer of the water column in which there is sufficient sunlight to support net productivity. The position of the organisms in the euphotic zone is influenced by the action of wind and waves. In addition, many phytoplankton are capable of active movements that enhance their productivity and, therefore, their survival.
Exposure to solar UVB radiation has been shown to affect both orientation mechanisms and mobility in phytoplankton, resulting in reduced survival rates for these organisms. Scientists have demonstrated a direct reduction in phytoplankton production due to ozone depletion-related increases in UVB and studies have indicated a 6-12% reduction in the marginal ice zone.
Solar UVB radiation has been found to cause damage to early developmental stages of fish, shrimp, crab, amphibians and other animals. The most severe effects are decreased reproductive capacity and impaired larval development. Even at current levels, solar UVB radiation is a limiting factor, and small increases in UVB exposure could result in significant reduction in the size of the population of animals that eat these smaller creatures
Plankton, organisms that live on carbon, light, and nutrients such as nitrogen, are near the bottom of the food chain, and are accustomed to low levels of UV. Increased levels of UV radiation therefore decreases the number of photo plankton.
Phytoplankton is the main source of food for krill, which in turn are the main source of food for various birds, fish and whales. A decrease in phytoplankton results in starvation for other marine species.
The impact of harmful UV rays on a marine ecosystem is a perfect example of the entire food chain being affected due to an increase in the UV radiation as a result of the thinning ozone layer.