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Life on Earth depends upon one–way flow of high–quality energy from sun & cycling of crucial elements. Nitrogen and Phosphorus…These elements are essential to function and productivity of ecological systems. Importance of Phosphorus (P) Like nitrogen, phosphorus (P) is an essential part of the process of photosynthesis. Involved in the formation of all oils, sugars, starches, etc. Helps with the transformation of solar energy into chemical energy; proper plant maturation; withstanding stress. Importance of Phosphorus (P) Effects rapid growth. Encourages blooming and root growth. Phosphorus originates from rocks Hydrosphere- water layer. Liquid, Ice, Vapor. Lithosphere- Earth’s crust and upper mantle. - Fossil fuels, minerals, soil chemicals. Biosphere- biotic & abiotic factors. Phosphorous Cycle Never enters the atmosphere Atmosphere Biosphere Absorption Waste & Decomposition Weathering & Erosion Hydrosphere Lithosphere Absorption Sedimentation Human Impacts Phosphorous Cycle Net Effect: Increase in phosphorous in water & “algal blooms”; Depletion in soils Biosphere Mining, use (fertilizer, detergent, etc.) & increased runoff Lithosphere Hydrosphere More Phos. for organisms The phosphorus cycle does not have a gas phase, but small amounts of phosphoric acid rise into the atmosphere, contributing to acidic precipitation. The water, carbon, and sulfur cycles all include at least one phase in which the element is in its gaseous state. The largest reservoir of phosphorus is in sedimentary rock. The Cycle Simplest of the cycles Phosphorus has only one form – phosphate ◦Always part of an organism, dissolved in water, or in the form of rock Phosphorus enters environment from rocks or deposits Apatite is the phosphate rock where phosphate is available Weathering and erosion releases phosphate ions that are soluble in water Phosphate then acts as fertilizers or nutrients for land plants It gets incorporated into molecules essential for life like ATP, adenosine triphosphate – this is important in storage and use of energy Phosphate is in backbone of DNA and RNA When animals and plants die, phosphates will return to the soils or oceans again during decay Phosphorus cycles through plants and animals much faster than it does through rocks and sediments.. A lot of phosphate goes into the water from erosion and leaching Water plants use this phosphate as nutrients Phosphate is the limiting agent in growth of plants and algae If there is a lack of phosphate, plants grow slowly or are stunted If too much, excess growth may occur Phosphate in water is precipitated from water as ion phosphate (insoluble) Phosphate in shallow sediment may be recycled into water In deep sediment in water, it is available as part of as part of rock formations for cycle to repeat After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years. Eventually, phosphorus is released again through weathering and the cycle starts over. Major components of aquatic ecosystems. Fig. 4–11 Major components of terrestrial ecosystems. Fig. 4–12 Human influences on phosphate cycle mostly comes from introduction & use of commercial synthetic fertilizers. Phosphate obtained by mining at certain deposits of calcium phosphate called apatite. Phosphate rock and sulfuric acid are combined to make a fertilizer called “super phosphate.” There are many negative effects of using this fertilizer. A lot of the fertilizer is lost through the water run-off because plants aren’t able to use up all of it. Eventually the wasted phosphate in the water is precipitated as it settles at the bottom of the body of water. Component Input to soil Loss from soil The Phosphorus Cycle Crop harvest Animal manures and biosolids Atmospheric deposition Mineral fertilizers Plant residues Organic phosphorus •Microbial •Plant residue •Humus Leaching (usually minor) Plant uptake Soil solution phosphorus •HPO4-2 •H2PO4-1 Primary minerals (apatite) Runoff and erosion Mineral surfaces (clays, Fe and Al oxides, carbonates) Secondary compounds (CaP, FeP, MnP, AlP) Phosphorus Cycle How and in what form(s) does phosphorus enter and leave the cycle? How do the roles of autotrophs and heterotrophs differ? What are the human impacts on the cycle?