Effects Of Acid Rain On Biodiversity Contents ● What is acid rain? ● Causes of acid rain ● How does it affect Biodiversity and the environment? ● How do we minimize it? ● Conclusion ● References What is Acid Rain? Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents. The SO2 and NOX react with water, oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground. What causes Acid Rain? The primary cause of acid rain is air pollution. Natural sources of acid rain include erupting volcanoes that contain some chemicals which can cause acid rain. Since this is not a frequent phenomena, leading causes of acid rain today are due to human activities. Burning of fossil fuels, the running of factories and automobiles are a few other reasons behind acid rain. Forms of Acid Deposition Wet Deposition Wet deposition is what we most commonly think of as acid rain. The sulfuric and nitric acids formed in the atmosphere fall to the ground mixed with rain, snow, fog, or hail. Dry Deposition Acidic particles and gases can also deposit from the atmosphere in the absence of moisture as dry deposition. The acidic particles and gases may deposit to surfaces (water bodies, vegetation, buildings) quickly or may react during atmospheric transport to form larger particles that can be harmful to human health. How does it impact biodiversity? Acid rain causes a cascade of effects that harm or kill individual fish, reduce fish population numbers, completely eliminate fish species from a waterbody, and decrease biodiversity. The ecological effects of acid rain are most clearly seen in the aquatic, or water, environments, such as streams, lakes, and marshes. Acid rain flows into streams, lakes, and marshes after falling on forests, fields, buildings, and roads. Acid rain also falls directly on aquatic habitats. Acid rain primarily affects sensitive bodies of water, which are located in watersheds whose soils have a limited ability to neutralize acidic compounds i.e. buffering capacity. Lakes and streams become acidic when the water itself and its surrounding soil cannot buffer the acid rain enough to neutralize it. In areas where buffering capacity is low, acid rain releases aluminum from soils into lakes and streams; aluminum is highly toxic to many species of aquatic organisms. Some types of plants and animals are able to tolerate acidic waters. Others, however, are acid sensitive and will be lost as the pH declines. pH tolerance of some aquatic animals Together, biological organisms and the environment in which they live are called an ecosystem. The plants and animals living within an ecosystem are highly interdependent. For example, frogs may tolerate relatively high levels of acidity, but if they eat insects like the mayfly, they may be affected because part of their food supply may disappear. Because of the connections between the many fish, plants, and other organisms living in an aquatic ecosystem, changes in pH or aluminium levels affect biodiversity as well. Thus, as lakes and streams become more acidic, the numbers and types of fish and other aquatic plants and animals that live in these waters decrease. The Shannon index (H’) is used to evaluate the biodiversity within an environment. The higher the value of this index, the greater the biodiversity. The graph below shows the Shannon index applied to benthic macroinvertebrates (invertebrates living on the bottom of watercourses) as a function of the acidity of a watercourse. We can see here that the lower the pH of the watercourse, the lower the biodiversity (Gerold, 2010). Similarly, the higher the aluminium concentration, the lower the biodiversity. Finally, the lower the concentration of calcium or magnesium, the lower the biodiversity. An acidified river or lake, therefore, has a low biological diversity. Effect on Forests Acid rain makes trees vulnerable to disease, extreme weather, and insects by destroying their leaves, damaging the bark and arresting their growth. Forest damage due to acid rain is most evident in Eastern Europe – especially Germany, Poland and Switzerland. 3. Effect on Soil Acid rain highly impacts soil chemistry and biology. It means soil microbes and biological activity as well as soil chemical compositions such as soil pH are damaged or reversed due to the effects of acid rain. High soil acidity also denatures enzymes for the soil microbes. On the same breadth, hydrogen ions of acid rain leach away vital minerals and nutrients such as calcium and magnesium. Episodic Acidification Melting snow and heavy rain downpours can result in what is known as episodic acidification. Lakes that do not normally have a high level of acidity may temporarily experience effects of acid rain when the melting snow or downpour brings greater amounts of acidic deposition and the soil can’t buffer it. This short duration of higher acidity can result in a short-term stress on the ecosystem where a variety of organisms or species may be injured or killed. Solutions to the problem Since Acid Rain and air pollution are directly correlated, decreasing air pollution will also result in a decrease of acid rain. Alternative Energy Sources Besides fossil fuels, there is a wide range of alternative energy sources that can generate electrical power. These include wind energy, geothermal energy, solar energy, hydropower, and nuclear power. Individual, National/State, and International Actions Millions of people, directly and indirectly, contribute to SO2 and NOx emissions. Mitigation of this challenge requires individuals to be more informed about energy conservation and ways of reducing emissions such as: turning off lights or electrical appliances when not using them; use public transport; use energy-efficient electrical appliances; and use of hybrid vehicles or those with low NOx emissions. Conclusion As of today, all energy sources have environmental and economic costs as well as benefits. The only solution is using sustainable energy that can protect the future. This will cause major air pollution causes to diminish and greatly reduce acid rain. Less acid rain will help protect and sustain habitats and minimise disruptions in the food chain. This will lead to protection of biodiversity and prevent the loss of species from man-made causes. References https://www.epa.gov/acidrain/what-acid-rain#:~:text=Acid%20rain %2C%20or%20acid%20deposition,even%20dust%20that%20is% 20acidic. https://www.conserve-energy-future.com/causes-and-effects-of-ac id-rain.php https://landuse.alberta.ca/Forms%20and%20Applications/RFR_A CFN%20Reply%20to%20Crown%20Submission%205%20-%20T abD9%20AcidRain_2014-08_PUBLIC.pdf https://volcanofoundation.org/acid-rain-biodiversity/
