Marine life may be effected as increased levels of UV radiation could destroy plankton in the top water layer of the ocean breaking a key link in the food chain. UV's impact on plankton may reduce the ocean's ability to absorb CO2. If this significant function of the ocean is crippled, the greenhouse effect and global warming could worsen. The amount of ultraviolet radiation reaching a particular point on the earth's surface on a given day is determined by many variables. On a clear day the level of UV radiation reaching the ground depends on how direct the sun's rays are.
Rays hitting the earth directly, naturally, have more energy than less direct rays.
They move through less energy filtering atmosphere than lower angled rays. The directness of the sun's rays is determined by three major factors, the time of day, the time of year and the location's latitude. This is the moment in time when the sun's rays are most direct. Before and after this date and time the sun hits the area at lower angles, less directly, decreasing the radiation. In general, the closer one moves towards the equator the more direct the sun's rays will be.