Chapter 2: Energy Flow and Nutrient Cycles Support Life in Ecosystems
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Today Virtual lab http://www.mhhe.com/biosci/genbio/virtual_labs/BL_03/BL_03.html Diagram page 76 textbook Nutrient cycling (CARBON) Stores 6 main processes C is cycled Anthropogenic effects Workbook pages
A 54-year old sealed terrarium (planted in 1960) no fresh air or water http://i.dailymail.co.uk/i/pix/2013/01/24/article-2267504-17212EB3000005DC-781_634x663.jpg
2.2 Nutrient Cycles in Ecosystems Earth’s biosphere acts like a sealed terrarium where nutrients and wastes are recycled Carbon, nitrogen and phosphorus cycles move nutrients in and out of terrestrial and aquatic ecosystems Where does the water you drink come from?
2.2 Nutrient Cycles in Ecosystems Human activities can upset the natural balance of nutrient cycles: - land clearing - agriculture - industry - motorized transportation
Nutrient Cycling Nutrients: chemicals that are needed for plant and animal growth and other life processes. Are accumulated in atmosphere, oceans, and land masses Stores: location of nutrient accumulation
Nutrient Cycling Nutrient Cycling: movement in and out of stores Caused by biotic and abiotic processes Cycles are near balance (input = output) You need to know about C, N, & P cycles But O and H are also needed for life
Carbon Cycle
Carbon Stores All living things contain carbon in their cells How carbon is stored: Short term stores - vegetation on land, in oceans - animals and decaying OM in soil - atmosphere as CO2 - top layers of ocean
Carbon Stores Long-term stores: - intermediate and deep oceans - coal deposits - marine deposits and sedimentary rock
Amount of C /Gigatonnes Carbon Stores Store Amount of C /Gigatonnes Marine sediments and sedimentary rock 68 000 000 to 100 000 000 Oceans (intermediate/deep) 38 000 to 40 000 Coal Deposits 3 000 Soil and organic matter 1 500 to 1 600 Atmosphere 750 Terrestrial Vegetation 540 to 610 Oil and Gas Deposits 300 Giga = 1 billion or 109 Where is most carbon stored?
Carbon Stores Sedimentation: Traps many long-term carbon stores Layers of soil/decomposing OM get buried turn into rock/coal/oil/gas by SLOW geological processes
Carbon Stores Limestone (CaCO3 ) forms from shell deposits on ocean floor Long-term carbon stores are aka carbon sinks
Carbon Cycle Carbon is cycled through ecosystems by: Photosynthesis Cellular respiration Decomposition http://grandaspirations.org/wp-content/uploads/2010/11/growing-plant.jpg http://static.guim.co.uk/sys-images/Guardian/Pix/pixies/2010/1/4/1262629202528/A-gulls-breath-on-a-cold--001.jpg
#1) Photosynthesis Sun + 6H20 + 6CO2 → C6H12O6 + 6O2 chemical reaction in plants and cyanobacteria where sunlight (solar energy) is used to make glucose (chemical energy) Sun + 6H20 + 6CO2 → C6H12O6 + 6O2 (sun + water + carbon dioxide → sugar + oxygen)
#1) Photosynthesis recycles carbon and oxygen through ecosystems By eating plants, consumers obtain energy and take carbon into their cells.
Giga = billion
#2) Cellular Respiration Opposite of photosynthesis chemical reaction in mitochondria of cells where oxygen is used to liberate energy from glucose. 6O2 + C6H12O6 -> 6CO2 + 6H2O + energy
Giga = billion
#3) Decomposition the breaking down of dead organic matter Decomposers (bacteria + fungi) convert organic molecules (carbohydrates) back into carbon dioxide.
Giga = billion
Today Nutrient cycling (CARBON) Review 6 main processes C is cycled What are YOU doing? PHosphorUs and Nitrogen (Phun with a P-H!)
You’re the next contestant! http://www.bcscience10.com/docs/puzzles/section02_1_puzzle/index.html One lucky volunteer gets to click the link and be the host while I check WB 24-26 You have 10 minutes…
Other ways carbon is cycled #4) Ocean processes (CO32-) sediments, marine organisms remember CaCO3! We made some in a lab. #5) Volcanic eruptions release CO2 #6) CO2 is rapidly released during forest fires (slowly for decomposing trees)
Giga = billion
Human activities and the carbon cycle Industry, motorized transportation, land clearing Industrial revolution (160 yrs ago) CO2 levels increased by 30% from increase of fossil fuel burning Increase in CO2 in the previous 160 000 ya was 1-3% We release C from long-term stores FAST (coal, oil, gas)
Anthropogenic effects Burning fossil fuel reintroduces C to the cycle that was removed in a long term store CO2, a greenhouse gas, is the most common form of carbon absorbs heat in atm. Contributes to global climate change
Anthropogenic effects? Clearing land reduces amount of carbon taken from atmosphere by plants during photosynthesis Farm plants remove CO2, but less than natural vegetation
Agriculture: cows are carbon culprits Our obsession with cows is causing almost 10% of global warming emissions http://qz.com/128662/our-obsession-with-cows-is-causing-almost-10-of-global-warming-emissions/#/h/15425,1/ Cows release methane from digestion (23x stronger than CO2) Feed is not environmentally friendly
Giga = billion
Breaking down the carbon cycle http://www.bcscience10.com/media/EP_carbon_cycle.swf
http://qz.com/128662/our-obsession-with-cows-is-causing-almost-10-of-global-warming-emissions/#/h/15425,1/
Carbon cycle http://www.bcscience10.com/protect/flash_u1_carbon_cycle.html
Today Nutrient cycling (CARBON) Review 6 main processes C is cycled What are YOU doing? PHosphorUs and Nitrogen (Phun with a P-H!) BONUS CHALLENGE… tell me what you learned about nutrient cycling from THE link that was NOT covered in class (5 marks maximum, handed in at beginning of next class)
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