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3-3 Cycles of matter Recycling in the Biosphere • Unlike the one-way flow of energy, MATTER is recycled • within and between ecosystems Biogeochemical cycles connect biology geology & chemistry P/S: what does ‘biogeochemical’ mean? Water cycle • Water is essential to all life • Fresh water from the oceans moves into the atmosphere by – Evaporation – Transpiration (leaves) condensation precipitation Nutrient cycles • Chemicals needed by living things to build tissues, carry out essential life functions circulate through the ecosystem Whiteboard: List the elements found in the diagram above Carbon cycle • Carbon is essential to life • CO2 moves from the air into plants • CO2 returns to the air with respiration, decomposition, and burning fuels Nitrogen Cycle N2 in Atmosphere Synthetic Synthetic fertilizer fertilizer manufacture manufacturer Uptake by producers Bacterial nitrogen fixation Decomposition Reuse by consumers Decomposition excretion NH3 Atmospheric nitrogen fixation Uptake by producers Reuse by consumers Decomposition excretion NO3 and NO2 Nitrogen cycle • N in the air is changed by • • • soil bacteria into ammonia Taken up by roots Animals eat their N when they eat plants Decay, feces return N back to the soil P/S: how are the C and N cycle similar? Different? Phosphorus Cycle • P is needed for • • DNA & RNA It is rare in the biosphere Most P is stored in rocks and ocean sediments Organisms Land Ocean Sediments Limiting nutrients Pygmy forest, Mendocino, CA • If a nutrient is scarce, it will limit growth in an ecosystem • Fertilizers add N, P, & K to crops to promote growth • TOO MUCH of a nutrient can alsoupset the balance: fertilizer runoff forms algal blooms in rivers and lakes Whiteboard: what caused the algal blooms you see here? Clear Lake, CA Human impact Human activity (burning fossil fuels, deforestation) has greatly impacted natural nutrient cycles, causing air, water, and soil pollution. Summary Today’s lecture was on nutrient _____________ I learned about ___________________________ I knew already that ______________________ I wonder about________________________________