HW 2 Submission deadline: Thursday Oct 12, 2023 10p for each question 1. Explain the carbon cycle and nitrogen cycle. The carbon cycle is basically the production of food energy by land plants. Through photosynthesis, the inorganic carbon in carbon dioxide plus water and energy from the sunlight is transformed into organic carbon with oxygen given off as a waste product. The chemical formula for photosynthesis is 6CO2 + 6H2O → C6H12O6 + 6O2. Plants and animals also engage in respiration. Animals use oxygen to convert the organic carbon in sugar into food energy. Plants also go through respiration and consume some sugars. The chemical reaction for respiration is C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + useable energy. Both processes are gas exchange processes. There are carbon reservoirs for example, the ocean, rock, animals, and the atmosphere. The plants or ocean or lakes. etc take the carbon in. They let off carbon through respiration, then when the animal dies, after a long period of time they can be converted into fossil fuels, that produce carbon dioxide. The nitrogen cycle is the primary gas in the atmosphere. For example, in plants, the bacteria live inside the roots. Nitrogen in the atmosphere is fixed by bacteria called ammonia from the roots of plants and fix it to nitrates. Animals then eat the plants and obtain the nitrogen then both plants and animals decompose in ammonification. There are other types of bacteria in the soil as well. For example, denitrifying bacteria in the soil can convert nitrates and nitrites back into atmospheric nitrogen gas. There are other ways that nitrogen can cycle. 2. Explain the water cycle, and do also explain how the carbon cycle and water cycle together affect the climate. The water cycle which is also called the hydrologic cycle is a cycle that involves the continuous circulation of water in the earth-atmosphere system. The water cycle is a complex system that includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow. Water in different phases moves through the atmosphere through transportation. Liquid water then flows across land (runoff), into the ground (infiltration and percolation), and through the ground. Groundwater moves into plants (plant uptake) and evaporates from plants into the atmosphere (transpiration). Solid ice and snow can turn directly into gas (sublimation). The opposite can also take place when water vapor becomes solid (deposition). The carbon cycle plays a key role in regulating Earth's global temperature and climate by controlling the amount of carbon dioxide in the atmosphere. An increase in water evaporation affects the water cycle. If water evaporation is happening at a faster rate that means precipitation is affected. Warmer air can hold more water vapor which can lead to stronger and more intense storms. These storms can cause massive floods in different climates which affects the natural systems of the areas. 3. Why is the ocean very important for the carbon cycle? The ocean plays a huge role in the carbon cycle. The ocean holds about 50 times more carbon than the atmosphere. Carbon dioxide from the atmosphere dissolves in the surface waters and some of it stays as dissolved gas but much of it gets turned into other things. Photosynthesis takes place by marine plants and turns carbon dioxide into organic matter. 4. How do humans influence the phosphorus cycle? Humans release mined phosphates into ecosystems, especially in the forms of fertilizers but also other types of waste. Extra nitrogen gets into runoffs and waterways and contributes to eutrophication. Acidic precipitation can be caused by natural volcanoes and man-made activities such as cars and the generation of electricity. 5. How does acid rain form? It is caused by the release of sulfur dioxide and nitrogen oxides into the atmosphere where they react with water, oxygen, and other chemicals to become sulfuric and nitric acid respectively. General guidelines: This HW is rather short. You should be able to explain the cycles asked for in words only, or in a drawing together with relevant information.
