absorbing the UV rays, UV-C never reaches the Earth's surface. The effects of ozone depletion are likely to be most

devastating to organisms that are exposed to sunlight during their developmental stages. The sea urchin embryos are

transparent and poorly protected against UV. Sea urchins are exposed to UV radiation during all stages of their lifecycle.

Sea Urchins like many organisms have DNA repair enzymes, photolyases. UV radiation causes direct damage to proteins

and DNA by creating the formation of pyrimidine dimers and crosslinks between DNA and protein. Consequences of

these mutations are delayed cell divisions, DNA damage, developmental delays, and abnormalities. UV treatment can

cause immediate effects by damaging microtubules and long term effect by damaging RNA and DNA.

Tyler, Mary, S. . Sunderland: Sinauer Associates Inc., 2000. P73-80.

Gilbert, Scott F.