Effect of the Ozone Hole on Oceanic Life

As ozone is the only atmospheric gas that appreciably absorbs ultraviolet (UV) radiation, it is critical in protecting living organisms from excessive exposure. UV photons are sufficiently energetic that they damage DNA, the genetic material present in all living cells. The radiation can cause skin cancers and immune system damage in humans. Similarly, UV radiation is damaging to tissues and to the functions of plants and animals. While the most pronounced decrease in ozone concentration is associated with the Antarctic "ozone hole," ozone depletion has also been documented in the Arctic.

The NSF UVRadiation Monitoring Network was initiated in 1988 to provide direct measurements of UV radiation reaching the earth's surface. The network instruments are now located at the three US Antarctic stations as well as in southern Argentina and Barrow, Alaska. Data from Antarctica clearly confirm an increase in UV radiation when the ozone hole develops.

The effect of UV radiation on the marine ecosystem is a major focus of research in Antarctica. Microscopic marine plants, or phytoplankton, form the base of the food web. Dependent on sunlight for photosynthesis, phytoplankton are restricted to the upper layers of the ocean where UVB radiation penetrates with the sunlight. Even a small decrease in phytoplankton productivity due to UV exposure could have significant effects. A decrease could be relayed through the food web and affect larvae, fish, crabs, birds, and mammals, which could affect the global food supply.

Using realtime data from NASA satellites and the NSF network, research ships were able to follow the "footprint" of the ozone hole to conduct experiments of UV effects on marine plants and organisms. Measurements of phytoplankton growth under increased UV concentrations due to the ozone hole showed a decrease of 6 % to 12% compared to normal concentrations outside the ozone hole. Similar results were found in studies of phytoplankton growth near McMurdo Station. The ecological significance of this effect is currently being debated among scientists. Future studies will focus on other components of the marine ecosystems such as fish and invertebrate larvae living in the near-surface oceanic waters surrounding Antarctica.

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