Assessment State Explain that energy enters and leaves ecosystems, but nutrients must be recycled State that saprotrophic bacteria & fungi recycle nutrients Nutrient Cycles Nutrient Cycles • All the chemical substances that an organism needs to sustain life are its nutrients. • Every living organism needs nutrients to build tissues and carry out essential life functions. • Nutrients are passed between organisms and the environment through biogeochemical cycles. Nutrient Cycle Nutrient Cycle vs. Food Chain Food Chain Decay & Decomposition • All living organisms die – the environment reclaims the nutrients & returns them to the ecosystem Decay & Decomposition • Nutrients from dead organism are recycled by a series of processes carried out by other living organisms. Process of Decay: 1. Scavengers – Breakdown dead body to a more manageable pieces Process of Decay: 2. Decomposers (saprotrophic bacteria and fungi)-- Break down what the scavengers leave behind. Decomposition and Carbon Some decomposition of dead organisms is similar to the process of respiration: Dead organism + O2 CO2 + H2O (Hydro-Carbons) • Decomposition is a process where the carbon from the dead organism is broken down by a microorganism using Oxygen & a carbon dioxide and water is released. Decomposition and Nitrogen Other decomposition of dead organisms breaks down proteins and releases nitrogen into the soil in the form of Ammonium (NH4) Saprotrophic Microorganisms that do Decomposition – Fungus – Bacteria – Other small organisms The Carbon Cycle CO2 in Atmosphere Photosynthesis feeding Volcanic activity Respiration Decomposition Human activity Erosion CO2 in Ocean Respiration Uplift Deposition Photosynthesis Fossil fuel feeding Deposition Carbonate Rocks Online tutorial of global Carbon Cycle http://www.sumanasinc.com/webcontent/an imations/content/globalcarboncycle.html Copyright Pearson Prentice Hall Assessment Statement: Draw and Label a diagram of the carbon cycle to show the processes involved. Copyright Pearson Prentice Hall Carbon is found in one of four 'pools': 1.Biosphere 2.Oceans 3.Atmosphere 4.Sediments • carbon is moved between these four pools by a variety of biological, geochemical or industrial processes. Copyright Pearson Prentice Hall Nutrient Cycles The Carbon Cycle Carbon is a key ingredient of living tissue. Nutrient Cycles The Carbon Cycle Six Biological processes take up and release carbon such as 1. 2. 3. 4. 5. 6. photosynthesis, Respiration Decomposition Death Excretion Feeding All living things Respire Carbon Dioxide from Respiration Write equation: All living things Respire Carbon Dioxide from Respiration Write equation: Photosynthesis/ Carbon fixation By AUTROTROPHS Plant Material Photosynthesis Equation: Photosynthesis/ Carbon fixation By AUTROTROPHS Plant Material Photosynthesis Equation: Decomposition and Carbon Decomposition Some decomposition of dead organisms is similar to the process of respiration: Dead organism + O2 CO2 + H2O Excretion Process •Organisms put carbon back in the soil or water via waste-- Excretion Nutrient Cycles Death Process When organisms die, decomposers return carbon to the soil and atmosphere (CO2) Feeding – animals, bacteria, fungi – all heterotrophs get carbon through eating it. Copyright Pearson Prentice Hall Geochemcial Process Geochemical processes, such as the –burial and decomposition of dead organisms and their conversion under pressure into coal and petroleum (fossil fuels), store carbon underground. Carbon sources: Fossil Fuels Coal Formation – Deposition of Ancient fossilized plants Forms Of Carbon Coal (fossil fuels) Human Activities Human activities, such as mining, cutting and burning forests, and burning fossil fuels, release carbon dioxide into the atmosphere. Forms of Carbon Sources of Carbon Dioxide Burning Fossil Fuel (example: Cars) Production of Methane (CH4) by Methanogenic archeans Copyright Pearson Prentice Hall Production of Methane Copyright Pearson Prentice Hall Production of Methane Methane is oxidized into Carbon Dioxide and water in the atmosphere. Methane molecules will persist in the atmosphere for about 12 years and then they are naturally oxidized by monatmoic oxygen Copyright Pearson Prentice Hall Peat Formation Peat formation occurs • when soils become water logged/ saturated and anaerobic (no oxygen for decomposition or respiration) • Saprotrophs cannot survive without oxygen • Dead organic matter can not be decomposed in these anaerobic conditions and so it accumulates in the form of compressed dark brown acidic material called peat • Many places on earth are covered with peat. So large amounts of carbon is locked up in peat. Copyright Pearson Prentice Hall Limestone –Calcium Carbonate Rock • Rock formed from reefbuilding coral animals and molluscs. • When these animals die their calcium carbonate skeleton accumulate and over long periods of time are compressed into rocks. • Large amounts of carbon are locked up in these rocks. Copyright Pearson Prentice Hall Assignment: Draw and Label a diagram of the carbon cycle to show the processes involved. Be sure to include the below processes: • Cellular Respiration • Decomposition • Excretion • Feeding • Combustion • Photosynthesis/ carbon fixation • Death • Methane production • Peat Formation • Limestone formation Copyright Pearson Prentice Hall Assessment Statement 5.2.3 Explain the relationship between rises in concentration of atmospheric carbon dioxide using historical records. Copyright Pearson Prentice Hall Carbon Dioxide Levels (ppm) Yearly changes in the Carbon Dioxide: Why do the carbon dioxide levels go up & down in our atmosphere over the course of a year? winter Spring time Seasonal Changes in Carbon Dioxide FALL/ WINTER SPRING/ SUMMER Copyright Pearson Prentice Hall Carbon Dioxide Levels (ppm) Changes in Carbon Dioxide in our Atmosphere in the last 100+ years. Why has carbon dioxide increased? Nutrient Cycles CO2 in Atmosphere Photosynthesis feeding Volcanic activity Respiration Decomposition Human activity Erosion CO2 in Ocean Respiration Uplift Deposition Photosynthesis Fossil fuel feeding Deposition Carbonate Rocks Copyright Pearson Prentice Hall Copyright Pearson Prentice Hall Assessment Statement 5.2.3 Explain the relationship in the rises in greenhouse gases and the enhanced greenhouse effect. Copyright Pearson Prentice Hall The greenhouse effect 1.Solar radiation travels to the surface of the earth. 2.This radiation is absorbed by the earth’s surface. 3.Earth’s surface emits (releases) radiation in the form of Infrared radiation(also called heat) 4.This infrared radiation (heat) tries to leave earth but gets trapped by the greenhouse gases. 5.The heat is trapped close to earth’s surface and thus, keeps the planet warm. Types of Solar Radiation Copyright Pearson Prentice Hall Who are greenhouse gases? Methane Carbon Dioxide Nitrogen Oxides Sulfur Oxides The Greenhouse Effect Explained a) Short wave solar radiation (light) b) light penetrates the atmosphere and passes through the molecules of the atmosphere c) Absorption by the ground and conversion to long wave infrared radiation (heat) d)This warms the planet e) Some infrared is lost to space as heat f) Atmospheric gases particularly, carbon dioxide, methane and nitrogen oxides. g) Greenhouse gases absorb infra-red radiation and scatter this rather than letting it escape to space. In effect this traps the heat energy. h) Some light reflects off the outer surface of the atmosphere and never enters Note that if this 'greenhouse' effect did not exist the average global temperature would be -17 C. Copyright Pearson Prentice Hall Green House Effect on other planets in our solar system Copyright Pearson Prentice Hall Enhanced Greenhouse Effect • Enhanced greenhouse effect is the concern that the activities of human's may be increasing the levels of carbon dioxide and other 'greenhouse gases’ in the atmosphere. • That this may lead to increased global temperatures and climate change Copyright Pearson Prentice Hall The enhanced greenhouse effect. • Increase in carbon dioxide and other greenhouse gases (methane, oxides of nitrogen) will increase the particles in the greenhouse gas layer • Therefore more infra-red will be absorbed, scattered and retained as heat. • The average global temperatures will rise. Some models suggest as much as 40C in the next 50 years. • An enhanced greenhouse effect is predicted to cause global climate changes. This is often referred to as global warming but whilst the average global temperatures may rise the local effects may vary widely. Copyright Pearson Prentice Hall Online tutorial of greenhouse effect: http://earthguide.ucsd.edu/earthguide/diagr ams/greenhouse/ Copyright Pearson Prentice Hall Assessment Statement 5.2.4 Outline the precautionary principle. 'If the effects of human-induced change would be large, perhaps catastrophic, those responsible for the change must prove that it will not do harm before proceeding Copyright Pearson Prentice Hall Copyright Pearson Prentice Hall Assessment Statement 5.2.5. The precautionary principle and the greenhouse effect. Copyright Pearson Prentice Hall 5.2.5. The precautionary principle and the greenhouse effect • The 'Precautionary principle' suggests that the obligation actually falls on those accused of causing climate change (or enhanced greenhouse effect) to show that their actions are not causing damage. If we wait until it is proven that humans are causing climate change it will be too late to reduce the impacts. Is it better to respond now as a precaution even if in the long term it turns out that the case cannot be made. Copyright Pearson Prentice Hall • The Precautionary principle reverses the argument of the 'Burden of Proof'. • The 'Burden of proof' principle in which (in context) it is up to those who claim that there is climate change( due to human causes) to prove that this is the case. That there is no need to respond to request for action to reduce human impact until that case has been proven. • The precautionary principle argues that those responsible for an effect (global warning, climate change, enhanced greenhouse effect) have the obligation to show that what they are doing has causes no harm. Copyright Pearson Prentice Hall In context of the enhanced greenhouse effect then: • Skeptic approach: The 'burden of proof' lies with those claiming that harm is caused by those responsible for the enhanced greenhouse effect to provide evidence that this is in fact the case. In other words, the environmentalist need to provide conclusive evidence that the actions of the 'polluters' are causing harm to the environment. • Precautionary Principle Approach: Those allegedly responsible for causing the effects of the enhanced greenhouse effect are required to demonstrate that their action do not cause harm. This responsibility would then fall on a wide spectrum or Nation Government, Industries, Communities and individuals to demonstrate that their actions cause no harm. Copyright Pearson Prentice Hall Copyright Pearson Prentice Hall