Acid Rain Essay Research Paper Introduction What — страница 2

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springtime is an especially vulnerable time for many aquatic species since this is the time for reproduction for amphibians, fish and insects. Many of these species lay their eggs in the water to hatch. The sudden pH change is dangerous because the acids can cause serious deformities in their young or even annihilate the whole species since the young of many of such species spend a significant part of their life cycle in the water. Subsequently, sulfuric acid in water can affect the fish in the lakes in two ways: directly and indirectly. Sulfuric acid (H3SO4) directly interferes with the fish’s ability to take in oxygen, salt and nutrients needed to stay alive. For freshwater fish, maintaining osmoregulation is key in their survival. Osmoregulation is the process of maintaining

the delicate balance of salts and minerals in their tissues. Acid molecules in the water cause mucus to form in their gills and this prevents the fish to absorb oxygen as well. If the buildup of mucus increases, the fish would suffocate. In addition, a low pH will throw off the balance of salts in the fish tissue. Salts levels such as the calcium (Ca+2) levels of some fish cannot be maintained due to pH change. This results in poor reproduction – their eggs produced would be damaged; they are either too brittle or too weak. Decreased Ca+2 levels also result in weak spines and deformities. For example, crayfish need Ca+2 to maintain a healthy exoskeleton; low Ca+2 levels would mean a weak exoskeleton. Another type of salt N+ also influences the well-being of the fish. As

nitrogen- containing fertilizers are washed off into the lakes, the nitrogen stimulates the growth of algae, which logically would mean and increase in oxygen production, thus benefitting the fish. However, because of increased deaths in the fish population due to acid rain, the decomposition process uses up a lot of the oxygen, which leaves less for the surviving fish to take in. Indirectly, sulfuric acid releases heavy metals present in soils to be dissociated and released. For example, Aluminium (Al+2) is harmless as part of a compound, but because acid rain causes Al+2 to be released into the soils and gradually into the lakes, it becomes lethal to the health of the fish in the lakes. Al+2 burns the gills of the fish and accumulates in their organs, causing much damage. So,

although many fish may be able to tolerate a pH of approximately 5.9, this acid level is high enough to release Al+2 from the soils to kill the fish. This effect is further augmented by spring acid shock. The effect of acid rain can be dynamically illustrated in a study done on Lake 223, which started in 1976. Scientists monitored the pH and aquatic ecosystem of Lake 223. They observed that as the pH of the Lake Decrease over the years, a number of crustaceans died out because of problems in reproduction due to the acidity of the lake caused by acid precipitation. At a pH of 5.6, algae growth in the lake was hindered and some types of small died out. Eventually, it was followed by larger fish dying out with the same problem in reproduction; there were more adult fish in the lake

than there were young fish. Finally, in 1983, the lake reached a pH of 5 and the surviving fish in the lake was thin and deformed and unable to reproduce. This case study obviously illustrates the significant effect of acid rain on lakes and its aquatic ecosystem. Effect on Materials Acid rain also damages materials such as fabrics. For example, flags that are put up are being “eaten away” by the acidic chemicals in the precipitation. Books and age-old art that are centuries old are also being affected; the ventilation systems of the libraries and museums that hold them do not prevent the acidic particles from entering the buildings and so, they get in and circulate within the building, affecting and deteriorating the materials. Effect on Atmosphere Some of the constituents

of acid pollution are sulphates, nitrates, hydrocarbons and ozone. These exists as dry particles in the air and contribute to haze, affecting visibility. This makes navigation especially hard for air pilots. Acid haze also interferes with the flow of sunlight from the sun to the earth and back. In the Arctic, this affects the growth of lichens which in turn, affect the caribou and reindeer which feed on it. Effect on Architecture Acid particles are also deposited on to buildings and statues, causing corrosion. For example, the Capitol building in Ottawa has been disintegrating because of excess sulphur dioxide in the atmosphere. Limestone and marble turn to a crumbling substance called gypsum upon contact with the acid, which explains the corrosion of buildings and statues. In