Christopher Kim 11-22-177-2 Mr. CastilloThree-page Library Research Paper In my science fair project, I am studying the effect of ultraviolet (UV) rays on plants. Plants are the producers of a food web that depend on sunlight. This allows other animals (herbivores, carnivores, and omnivores) to feed off of them and each other. From background information, I know that without the plants in an ecosystem that depends on sunlight, the whole system would collapse. Since the plants are the base of the food web, every organism feeding upon the plant and those feeding on plants indirectly (e.g., carnivores using plant-eaters as a food source) would perish. Without the plants, there would be no organisms to feed on to start with. Plants use photosynthesis to make their own usable energy for growth, and store it without having to consume other organisms. Photosynthesis is the process in which sunlight is converted into glucose and oxygen. However, when plants absorb that sunlight, they are not getting all of what is actually being released by the sun. In the Earth’s atmosphere, there is something called the ozone layer, which blocks out UV rays that the sun emits. Usually, UV rays would be filtered by the ozone layer from entering this Earth, but recent studies show that human activities is affecting the ozone layer which is allowing more UV rays to enter our atmosphere. Ozone is composed of 3 oxygen molecules with the chemical formula O?. Ozone itself is produced in a variety of ways, but one way is when sources of high energy (such as lightning) cause molecules of dioxygen (2 oxygen molecules) to react with each other. There are many different ways ozone can be produced, but here is that example in a chemical formula: 3O? + energy ?2O?. A plant uses photosynthesis to turn carbon dioxide and water into glucose and oxygen, using sunlight which they then use to grow and develop. Sunlight, however, in a way is being filtered by the ozone layer in the Earth’s atmosphere. The ozone in the ozone layer helps to block and repel harmful UV rays.Chlorofluorocarbons are used as both refrigerants and solvents. They are most commonly used as aerosol propulsive. More specifically, aerosol spray manufacturers use chlorofluorocarbons to propel aerosol. In the 1970s, scientists discovered a huge decrease in the amount of ozone in the ozone layer. Scientists then started to blame the chlorofluorocarbons for this loss of ozone. It was later proved that when chlorofluorocarbons come into contact with UV rays from the sun, they break down into many chemical compounds including chlorine. When chlorine reacts with the oxygen atoms in ozone molecules, it destroys the ozone altogether. One atom of chlorine can destroy more than one hundred thousand ozone molecules. This then slowly begins to destroy the ozone layer, making ozone holes. Ozone holes are not the actual holes in the ozone layer, but rather certain areas in the ozone layer that has a slightly less concentration of ozone. Such thinner layers of ozone allows more UV rays to pass down to Earth exposing ecosystems’ inhabitants to higher doses of UV rays. This can more or less destroy a food chain because in ecosystems depending on sunlight, the plant is affected. In a plant, the leaf is the part that absorbs the sunlight and receives first-hand damage due to the exposure of the higher dose of UV rays. To be more specific, chloroplasts are microscopic structures in the leaf which contains a green chemical called chlorophyll that absorbs sunlight. The harmful UV rays would then causes the leaf to wither and die. With no other way to absorb the nutrients from sunlight, the plant would eventually die out. Even though scientists have knowledge on ozone depletion and the cause for it, not much is being done to prevent it. People are constantly using aerosol containers that have chlorofluorocarbons in them. Aerosol containers are widely-used for a variety of things, such as cleaners, hair spray, etc.. However, there has been efforts to reduce the usage of aerosol; in the Montreal Protocol on Substances that Deplete the Ozone Layer, numerous countries came together to sign and agree upon cutting down on the usage of chlorofluorocarbons. Even with this effort, chlorofluorocarbons are still being released to some extent and destroying more and more ozone molecules. This is weakening our ozone layer which could lead to the end of life on planet Earth. Without proper coverage from UV rays, the plants that depend on sunlight would wither and die, and then the whole food web from there would crumble. The only possibility to sustain life on Earth, if that happens, would be indoor farming, where artificial sunlight is produced and exposed to the plants. It might seem like a great idea but on the contrary, to have to grow every single plant in indoor farms would not only be a very costly job, but it would also take a very long time to set up. In addition, the animals that feed on plants would have to be living in the indoor farms because they would have to be able to eat the plants. The carnivores and omnivores would also have to live in the indoor farms making the indoor farms more of a man-made ecosystem. Doing this to every single ecosystem and biome in the world would be impossible, considering the time and resources required. Remaking every biome would also defeat the whole purpose of animals hunting in the wild because everything would be monitored by humans and could be modified. Without being able to hunt in the wild, animals will be confined to a certain area losing the whole purpose of nature. Another option to be researched and tested to help the ozone layer (that is not extremely costly and lengthy) would be to release ozone into the atmosphere using ozone generators. There would have to be a way to somehow transport ozone to the ozone layer located in the outskirts of Earth’s gravitational fields. Other than this, the only other way would be, for humans to just completely stop releasing chlorofluorocarbons overall. Plants are one of the most important factors of life on Earth to its role as the producers of many food webs. To damage one of their main sources of energy is not only harmful to them but also to us in the long run. The ozone layer protects it and we are destroying that. To have to manually fix the ozone layer would be almost impossible and to live in a world without it would be unbearable. The best way to restore the ozone layer would be to stop releasing chlorofluorocarbons (or harming it) and let nature take its course of naturally restoring ozone to the ozone layer.