Biogeochemical Cycles a Dr. Production

The Law of Conservation of Energy states that energy cannot be created or destroyed, but it can be transformed. The Law of Conservation of Matter states that elemental matter cannot created or destroyed, but it can be transformed. Unlike the one-way flow of energy, matter is recycled within and between ecosystems. Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles, Biogeochemical cycles - the cycling of chemicals through the biotic and abiotic portions of the ecosystem 1. Energy FLOWS through an ecosystem and nutrients CYCLE in an ecosystem. 2. In an Ecosystem the Three Primary Nutrient Cycles: The Water Cycle The Carbon (and Oxygen) Cycle The Nitrogen Cycle

Water cycle

A. EVAPORATION from lakes, rivers, and oceans. Liquid gas B. TRANSPIRATION evaporation from plants C. CONDENSATION Cloud Formation gas  liquid D. PRECIPITATION Rain, Snow, Sleet, Hail as water falls from the sky. E. RESPIRATION water from living things F. ABSORPTION into the ground or living things G. RUN OFF over the surface of the land Brain Pop Water Cycle

Carbon cycle

A. Photosynthesis when plants fix carbon dioxide into organic form B. Consumption when carbon is passed from plants to animals C. Fossil Fuels when organic carbon undergoes time pressure and heat D. Combustion produces CO2 due to burning of fossil fuels E. Decomposition bacteria and fungi F. Respiration as living things produce energy G. Greenhouse gases like CO2 and CH4 which contribute to global warming Carbon Cycle Brain Pop Carbon Cycle

1. What is the process by which plants convert carbon dioxide into energy-rich carbon compounds? 2. Explain what happens over millions of years to the carbon compounds in organisms that die and decompose. 3. What processes above release carbon dioxide into the atmosphere? 4. Identify two major reservoirs of carbon dioxide on Earth. 5. What are the forms in which carbon is found in the oceans? 6. How do plants and animal help to maintain a balance of carbon dioxide in the atmosphere? 7. Atmospheric carbon dioxide might produce a “greenhouse effect” by trapping heat near the Earth’s surface. What human activities might tend to increase the greenhouse effect?

Nitrogen cycle

Nitrogen Cycle Brain Pop Nitrogen 1. ALL organisms need nitrogen, an important nutrient, to make proteins and nucleic acids. 2. Most nitrogen is found in the atmosphere (78%) as N2, and most living things cannot use it. 3. Nitrogen-fixing bacteria (Cyanobacteria and Rhizobium) play a key role in the nitrogen cycle. They live in the soil and in the roots of some kinds of plants called “legumes”, such as beans, peas, clover, peanuts and alfalfa. These bacteria live in nodules or bumps on the roots of legume in a mutualistic relationship. 4. Nitrogen fixing bacteria convert nitrogen gas (N2) to ammonia (NH3) is called Nitrogen Fixation. Ammonia can be absorbed by plants from the soil, and used to make proteins, and enter the food web for consumers. 5. Although plants can use ammonia, they prefer to use nitrate, because plants think that nitrate (NO3)is GREAT! Nitrifying bacteria convert ammonia to nitrate in a process known as NITRIFICATION. 6. Consumers obtain nitrogen from the plants and animals they eat. 7. The process of the production of ammonia from organic compounds is called AMMONIFICATION & DECOMPOSITION. In addition to the ammonification of amino acids, other compounds such as nucleic acids, urea, and uric acid go through the ammonification process. 8. Nitrogen is returned to the atmosphere through DENITRIFICATION. Denitrification occurs when anaerobic bacteria (chemoautotrophs) break down nitrates and release nitrogen gas back into the atmosphere. 9. Plants can absorb nitrates and ammonia from the soil, but animals (including ourselves) CANNOT. Nitrogen Cycle Brain Pop Nitrogen

2. Why would increased nitrogen cause the algae to grow? Nitrogen, Farms, Fish, Bears, and Salmon Farmer A has a large farm on which he grows corn. Through his farm flows a small creek which empties into a lake. This farmer sprays nitrogen fertilizer on his crops several times a year. Due to the weather patterns where he lives it often rains within several days of the application of the fertilizer. The lake near him has been a major recreation area with clear water and good fishing. Recently, clear water has become brownish green with mats of algae floating on the surface by late summer, resulting in fish kills. In the fall and winter there are many dead fish floating on the surface of the lake and drifting to shore. Recreation at the lake is coming to a halt because of the murky water and the dead fish. Farmer B has a similar large farm in which he grows corn one year and soybeans the next. Through his farm also flows a small creek, which empties into a similar lake. This farmer does not spray any nitrogen fertilizer on his crops. He knows that soybeans have bacteria on their roots which take the atmospheric nitrogen and convert it into a form of nitrogen that the plants can use. The rainfall is similar to Farmer A’s area. The lake near him is and remains a major recreation area. The water is clear and there is good fishing. There is no algae floating in the late summer and there are no fish kills. 1. What is the most probable cause of the algae growing in the lake near farmer A’s farm? 2. Why would increased nitrogen cause the algae to grow? 3. What would cause the fish to die? 4. Why did the algae not increase in the lake near farmer B?

Phosphorus cycle

Oxygen Cycle

Resources Global Carbon Cycle Carbon Cycle Animation Carbon Cycle Tutorial Carbon Cycle and Global Warming Nitrogen Cycle