Cycles of Matter and Energy Flow: Chemical Cycling and the Carbon and Nitrogen Cycles

1. Lesson Overview 3.4 Cycles of Matter

2. Energy Flow & Chemical Cycling • Energy Flow in an Ecosystem: • First Law of thermodynamics: energy can not be created or destroyed only transferred or transformed • Conservation of Mass: matter can not be created or destroyed • Plants convert solar energy to chemical energy but the total amount does not change • Unlike energy, chemical elements are recycled in the ecosystem! • periodic table

3. Recycling in the Biosphere • Energy: one-way flow of energy in ecosystem • Nutrients: recycled within and between ecosystems • Biogeochemical cycles: involve both biotic & abiotic components • biological processes, geological processes, and chemical processes.

4. Biological Processes Biological processes consist of any and all activities performed by living organisms. These processes include eating, breathing, “burning” food, and eliminating waste products.

5. Geological Processes • Geological processes include volcanic eruptions, the formation and breakdown of rock, and major movements of matter within and below the surface of the earth.

6. Chemical and Physical Processes • Chemical and physical processes include the formation of clouds and precipitation, the flow of running water, and the action of lightning.

7. Human Activity • Human activities that affect cycles of matter on a global scale include the mining and burning of fossil fuels, the clearing of land for building and farming, the burning of forests, and the manufacture and use of fertilizers.

9. Oxygen • Oxygen participates in parts of the carbon, nitrogen, and phosphorus cycles by combining with these elements and cycling with them through parts of their journeys. • photosynthesis: process that provides Oxygen to the atmosphere • Oxygen is used in respiration by all multicellular forms of life, and many single-celled organisms as well.

15. water cycle

17. The Carbon Cycle Carbon cycle involves four major systems: (1) land and soil (lithosphere), (2) organisms (biosphere), (3) air (atmosphere) and (4) the ocean (hydrosphere). Carbon is a major component of all organic compounds, including carbohydrates, lipids, proteins, and nucleic acids. 18% of our bodies are made of carbon! Carbon atoms continually move through living organisms, the oceans, the atmosphere, and the Earth’s interior and crust. This movement is known as the carbon cycle. The paths taken by carbon atoms may take millions of years to complete. song

21. Carbon Cycle • C found in carbohydrates and proteins • Carbon is a waste product cellular metabolism. (CO2) • Decaying vegetation & high pressure of the layers slowly turn the material into what we know today as “coal”. • Mining ancient coal beds and burning coal releases the energy stored in the carbon compounds in the coal and reunites the carbon atom with oxygen in the air to form CO2 again. The CO2 is released to the atmosphere • Oceans soak up a tremendous volume of carbon to prevent too much CO2 from remaining in the atmosphere. Organisms use it to make calcium carbonate (CaCO3) shells • When they die, their shells sink to the bottom of the ocean floor to form sediments of limestone and natural chalk. Sediments are raised above sea level by tectonic activity and create large rock formations. Ex: white cliffs of Dover are gigantic chalk cliffs

25. & nucleic acids 78%

27. The Nitrogen Cycle • Atmospheric nitrogen N2 NH3 ammonia • Nitrogen fixation • Ammonia can be taken up directly by plants — usually through their roots. However, most of the ammonia is converted into nitrates or “fixed” • Bacteria of the genus Nitrosomonas oxidize NH3 to nitrites (NO2−). • Bacteria of the genus Nitrobacter oxidize the nitrites to nitrates (NO3−).

28. The Nitrogen Cycle • Atmospheric nitrogen fixation: Energy from lightning causes atmospheric nitrogen (N2) and water (H2O) to form ammonia (NH3) and nitrates (NO3). Precipitation carries the ammonia and nitrates to the ground, where they can be assimilated by plants.

29. Nitrogen Cycle • Denitrification reduces nitrates and nitrites to nitrogen gas, thus replenishing the atmosphere. • nitrates (NO3−) Atmospheric nitrogen N2 • Organic matter Atmospheric nitrogen N2

31. nitrogen cycle

33. The Nitrogen Cycle • Humans add nitrogen to the biosphere through the manufacture and use of fertilizers. • Excess fertilizer is often carried into surface water or groundwater by precipitation.

34. Acid Rain • Acid rain: precipitation with high levels of nitric and sulfuric acids • Caused by atmospheric pollution: • erupting volcanoes • burning of fossil fuels (cars, industries) • When fossil fuels burn, sulfur dioxide (SO2) and nitrogen oxides (NO2) are released into the atmosphere forming sulfuric and nitric acid. • Winds spread these across the atmosphere. • When acid rain reaches Earth, it flows across the surface in runoff water, enters water systems, and sinks into the soil.

35. Acid Rain • Acid rain has many ecological effects, but none is greater than its impact on lakes, streams, wetlands, and other aquatic environments. Acid rain makes waters acidic and causes them to absorb the aluminum that makes its way from soil into lakes and streams. Acid rain dissolves minerals in soils, and transports these to water sources. This may cause aluminum concentrations in rivers and lakes to rise. • Read more: http://www.lenntech.com/periodic/water/aluminium/aluminum-and-water.htm#ixzz2j2oqWZI0This combination makes waters toxic to crayfish, clams, fish, and other aquatic animals.

36. Nutrient Limitation • Ecologists are often interested in an ecosystem’s primary productivity—the rate at which primary producers create organic material. • If an essential nutrient is in short supply, primary productivity will be limited. • limiting nutrient: nutrient whose supply limits productivity

37. Nutrient Limitation in Soil • Most fertilizers contain large amounts of nitrogen, phosphorus, and potassium, which help plants grow better in poor soil. • Carbon is not included in chemical fertilizers because plants acquire carbon dioxide from the atmosphere.

38. Nutrient Limitation in Aquatic Ecosystems • Oceans are nutrient-poor compared to many land areas. • In the ocean and other saltwater environments, nitrogen is often the limiting nutrient. • In streams, lakes, and freshwater environments, phosphorus is typically the limiting nutrient.

39. Nutrient Limitation in Aquatic Ecosystems • Fertilizer runoff can result in an algal bloom—a dramatic increase in the amount of algae and other primary producers due to the increase in nutrients. • If there are not enough consumers to eat the algae, an algal bloom can cover the water’s surface and disrupt the functioning of an ecosystem.