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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 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 Carbon cycle • Carbon is • • essential to life It moves out of the air into plants Returns with burning, decomposition, respiration Nitrogen cycle • N in the ground is • • • changed by soil bacteria Taken up by plants Animals eat their N Decay, feces return N back to the soil 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 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 • If a nutrient is scarce, it will limit growth in an ecosystem • Fertilizers supply N, P, Potassium as they are needed for growth • TOO MUCH of a nutrient can upset the balance also: fertilizer runoff forms algal blooms in rivers and lakes