BIOCHEMICAL CYCLES

BIOCHEMICAL CYCLESThe movement of materials through the biotic (living) and abiotic (non-living) parts of an ecosystem

BIOCHEMICAL CYCLESBiogeochemical CyclesBiogeochemical Cycles are also known as Nutrient Cycles -They are the pathways that 4 materials vital to life follow through an ecosystem - - Carbon - Nitrogen - Phosphorus- WaterThese materials cycle through both biotic and abiotic reservoirs in an ecosystem -biotic reservoirs are the living things that these materials move through -abiotic reservoirs are the non-living things that these materials move through

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Carbon is the backbone for many of the most important molecules used by living things. carbohydrates, fats, protein, nucleic acidCarbon exists as CO2 in the atmosphere - CO2 in the atmosphere cant be used by living things it must be converted into a usable form - How does CO2 get converted? Photosynthesis in plants - CO2 is used to make glucose the carbon in glucose can be used by living things

CO2 in atmospherePhotosynthesisCellular RespirationCombustionCoal OilDeath & DecompositionFossil FuelsCO2 is absorbed in waterLimestoneCarbon CycleCarbon returns to the atmosphere- cellular respiration - combustion All living things are biotic reservoirsThe atmosphere and water are abiotic reservoirs Carbon Sink A sink is a part of the cycle which removes a nutrient from the cycle for long periods of time - Limestone - Fossil Fuels

7Carbon CycleThe carbon in fossil fuels has been stored in the earth for millions of years- Burning them for energy releases the CO2 back to the atmosphere - causing a rapid increase in CO2 in the atmosphere - CO2 is a greenhouse gas which traps heat, warming the Earth - Increasing CO2 is leading to Global Climate Change

Nitrogen is used by living things to make proteins and nucleic acids (DNA, RNA & ATP)Nitrogen exists in the atmosphere as N2. 78% of the atmosphere is N2 -the N2 molecule consists of two nitrogen atoms so tightly bonded that they will not react with other elements and so cant be used by living things. - N2 can be split, but requires large amounts of energy lightning can split N2 -Once split by lightning, the nitrogen atoms bond with other elements and become useable by living things This accounts for 5 6 % of all nitrogenavailable to living things11Nitrogen Cycle: Nitrogen Fixation - Certain bacteria contain the enzymes necessary to convert N2 into the nitrogen compound ammonia NH3 - these nitrogen fixing bacteria are found in the soil and in symbiotic relationships with certain plants primarily legumes, beans, peas etc. The ammonia can enter the food chain when plants assimilate it take it up and use it or be converted by bacteria into nitrate NO3 and then assimilated Nitrogen Cycle:Man-made NitrogenThe Haber Process Developed by Fritz Haber in 1909, this process joins N2 and H2 together to make ammonia ( NH3 ) - The elements are driven together under high temperature and high pressure - In the last 60 years the use of ammonia as fertilizer has become wide-spread. - It has allowed humans to produce large quantities of food. However, excess nitrogen leeches into ground water or runs off into lakes and the ocean causing great harm13