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Matter Cycles matter Matter Cycles • The Law of Conservation of Matter states that matter is neither created or destroyed • In biological systems, this also holds true • We will be focusing on four matter cycles, also called nutrient or biogeochemical cycles • These are the Carbon, Water (hydrological), Nitrogen and Phosphorus cycles The Carbon Cycle The Carbon (C) Cycle • Even though it cycles we are going to start in the atmosphere • CO2 (carbon dioxide) in the atmosphere is picked up by photoautotrophs and turned into sugars • These sugars support the building of C containing molecules that make up living organisms • Another organism eats the plants, transferring the C to the next organism The Carbon (C) Cycle • This C may be passed on to another organism if it gets eaten • CO2 is reenters the atmosphere by cellular respiration from most organisms • Dead organisms and waste decomposes and more CO2 is reenters the atmosphere • Fossil fuels are underground stores of C, when dug up are burned (combustion) as petroleum, natural gas or coal; they add additional C as to our environment as CO2 • Excess CO2 is absorbed in bodies of water The Carbon (C) Cycle • CO2 is an important Greenhouse gas helping keep the planet at a relatively stable temperature • Excess burning of fossil fuels by industry and transportation has increased the amount of ground level and atmospheric C on our planet and may be accelerating climate change. The Water Cycle (hydrological) The Water Cycle (hydrological) • Evaporation-water enters the atmosphere • Precipitation-water condenses and leaves the atmosphere as rain, sleet or snow and ends up on land and can – – Runoff into surface water or – Infiltrate (or percolate) into land as groundwater or – Freeze and accumulate as ice • Or ends up in the ocean or other surface water • Transpiration –water leaves plants and enters the atmosphere The Water Cycle (hydrological) • Humans interrupt the water cycle by • Over pumping ground water • Creating many impervious surfaces (buildings, concrete and asphalt) so that water cannot reenter the ground and refill ground water • Polluting available surface and ground water • Building dams • Growing thirsty plants where they are not adapted to grow The Water Cycle (hydrological) The Nitrogen Cycle The Nitrogen Cycle • 78% of the atmosphere is Nitrogen, N2, is the major source of this vital element which is essential to make proteins in all living organisms • There is ONLY one kind of organism that can take N2 from the atmosphere and they are called N fixing bacteria • These soil dwelling N fixing bacteria then make N available to plants The Nitrogen Cycle • Plants use the N, now as nitrate or ammonium and make proteins • These plants are eaten and the N as protein is passed on to the consumer • Lightning strikes can also fix atmospheric N2 in the soil • N2 can return to the atmosphere by denitrifying bacteria in wet soil • N can also returned to the soil by decomposition of waste or dead organisms The Nitrogen Cycle • Humans impact the N cycle by • Manmade fertilizer high in N • Burning of petroleum by internal combustion engines (cars) produces large amounts of N compounds that cause acid rain by forming nitric acid when mixing with water in the atmosphere The Phosphorus Cycle The Phosphorus Cycle • Unlike all the other matter cycles, Phosphorus, P, NEVER cycles through the atmosphere • P is important both as part of DNA and cell membranes • P is MOSTLY found in rock • P is an important limiting factor in plant growth The Phosphorus Cycle • P is picked up by plants from the soil • The plants are eaten and P is obtained by the consumers from eating the plants • Then the P goes to the next consumer • P renters the ground by waste or decomposition • Weathering of rock is vital for the P cycle as is the water cycle for the movement of P The Phosphorus Cycle • Humans impact the P cycle by adding large amounts of inorganic fertilizer high in phosphorus which enters surface and ground water • Farm animal waste from large farms is high in P and can also enter the water cycle • These large amounts of P can cause eutrophication, rapid and large growth plants and algae, of bodies of water which chokes out other aquatic life forms Cycles Wrap-up • biogeochemicals cycles video