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Ecosystems Studying organisms in their environment organism population community ecosystem biosphere Essential questions What limits the production in ecosystems? How do nutrients move in the ecosystem? How does energy move through the ecosystem? Ecosystem All the organisms in a community plus abiotic factors ecosystems are transformers of energy & processors of matter Ecosystems are self-sustaining what is needed? capture energy transfer energy cycle nutrients Ecosystem inputs constant energy flows input of through energy nutrients cycle Matter cannot Don’t forget laws of or bethe created Physics! destroyed nutrients can only cycle biosphere inputs energy nutrients Generalized Nutrient cycling consumers producers consumers decomposers nutrients nutrients ENTER FOOD CHAIN made available = made available to producers to producers Decomposition connects all trophic levels return to abiotic reservoir abiotic reservoir geologic processes Carbon cycle CO2 in atmosphere Diffusion Respiration abiotic reservoir: CO2 in atmosphere enter food chain: Combustion of fuels = photosynthesis carbon fixation in Industry and home Calvin cycle Photosynthesis recycle: return to abiotic: respiration Plants combustion Animals Dissolved CO2 Bicarbonates Photosynthesis Animals Plants and algae Carbonates in sediment Deposition of dead material Deposition of dead material Fossil fuels (oil, gas, coal) Nitrogen cycle Carnivores abiotic reservoir: N in atmosphere enter food chain: nitrogen fixation by soil & aquatic bacteria recycle: Herbivores decomposing & nitrifying bacteria return to abiotic: denitrifying bacteria Birds Plankton with nitrogen-fixing bacteria Atmospheric nitrogen Plants Death, excretion, feces Fish excretion Decomposing bacteria amino acids Ammonifying bacteria loss to deep sediments Nitrogen-fixing bacteria (plant roots) Nitrogen-fixing bacteria (soil) Nitrifying bacteria soil nitrates Denitrifying bacteria Phosphorus cycle Plants Land animals Soluble soil phosphate Loss in drainage fungi) Rocks and minerals Decomposers Phosphates (bacteria & fungi) in solution Animal tissue and feces abiotic reservoir: rocks, minerals, soil enter food chain: erosion releases soluble phosphate uptake by plants recycle: decomposing bacteria Animal tissue & fungi Urine and feces return to abiotic: loss toDecomposers ocean (bacteria and sediment Aquatic animals Plants and algae Precipitates Loss to deep sediment abiotic reservoir: surface & atmospheric water enter food chain: precipitation & plant uptake Solar energy recycle: transpiration return to abiotic: Evaporation evaporation & runoff Water cycle Transpiration Water vapor Precipitation Oceans Runoff Lakes Percolation in soil Groundwater Aquifer Transpiration Remember transpiration? Breaking the water cycle Deforestation breaks the water cycle groundwater is not transpired to the atmosphere, so precipitation is not created forest desert desertification QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Repairing the damage The Greenbelt Movement planting trees in Kenya restoring a sustainable ecosystem establishing democracy empowering women Wangari Maathai Nobel Peace prize 2004 Studying ecosystems Hubbard Brook Experimental Forest 7800 acres 38 acre deforestation Effects of deforestation 40% increase in runoff loss of water loss into surface water 80 nitrate levels in runoff Concentration of nitrate (mg/l ) 60x loss in nitrogen 10x loss in calcium 40 loss out of ecosystem! 4 Deforestation 2 Why is 0 nitrogen 1965 so important? 1966 1967 Year 1968 Ecosystem inputs energy flows through nutrients cycle biosphere inputs energy nutrients Energy flows through ecosystems sun secondary consumers (carnivores) primary consumers (herbivores) producers (plants) loss of energy loss of energy Food chains Trophic levels feeding relationships start with energy from the sun captured by plants 1st sun top carnivore Level 3 Secondary consumer carnivore Level 2 Primary consumer heterotrophs herbivore level of all food chains food chains usually go Level 1 Producer up only 4 or 5 levels inefficiency of energy transfer Level 4 Tertiary consumer all levels connect to decomposers autotrophs Decomposers Bacteria Fungi Gross Primary Production all of the light energy (sun/artificial light) that is converted to chemical energy (glucose) BY photosynthesis per unit of time. If you obtained the amount of sunlight that is actually photosynthesized into sugar in the plant in an "hour" then, that would be your amount of primary productivity. Gross Primary production is inefficient! Loss of energy between levels of food sun chain To where is the energy lost? The cost of living! 17% growth only this energy moves on to the next level in the food chain energy lost to daily living 33% cellular respiration 50% waste (feces) What IS Net primary productivity? Think about it! for cell respiration Once the sugars are made (remember to think about sugar as chemical energy ) these sugars/energy will be used in TWO ways by the plant - (needs some energy to kick it off and will then convert sugars/chemical energy to ATP in the mitochondria) AND in growth of new biomass (plant tissue). Net ecosystem production only include the energy used to make new biomass or plant tissue. It excludes that used in cell respiration and in feces. Video: In this video, this scientist talks about people USING net primary production (plant material) (3.5 min) Ecological pyramid Loss of energy between levels of food chain can feed fewer animals in each level 1 100 100,000 1,000,000,000 sun Humans in food chains Dynamics of energy through ecosystems have important implications for human populations how much energy does it take to feed a human? if we are meat eaters? if we are vegetarian? What is your ecological footprint?! Food webs Food chains are linked together into food webs Who eats whom? a species may weave into web at more than one level bears humans eating meat? eating plants? Any Questions?? We’re working on a lot of them! 2006-2007