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BIOGEOCHEMICAL CYCLES. BIOGEOCHEMICAL CYCLES. Law of conservation-atoms atoms neither created or destroyed Same atoms must be passed around again and again CHNOPS make up 98% of living biomass
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BIOGEOCHEMICAL CYCLES • Law of conservation-atoms atoms neither created or destroyed • Same atoms must be passed around again and again • CHNOPS make up 98% of living biomass • Biogeochemical cycles move atoms (matter, nutrients, CHNOPS) through the air, soil, water, rocks, and living organisms. • Recycling of atoms & flow of energy sustain life on earth
BASIC PROCESS • Producers incorporate atoms (inorganic form) from nonliving reservoirs and convert to organic molecules • Consumers eat producers • Decomposers break down organic molecules to return atoms (inorganic form) back to abiotic
What to look for in a cycle? • Why is nutrient important? • What are the reservoirs for the nutrient involved? • What are the driving forces that transfers nutrient from abiotic to biotic and back to abiotic • How have humans upset the natural cycling of particular nutrient? • Description of cycle
WATER CYCLE-Why important • Living things are 75% water • Hydrogen in water supplies protons and electrons for photosynthesis • Oxygen in water is released as free oxygen into air during photosynthesis • Major solvent in living things for chemical reaction to take place in cells and transport • Homeostasis-high specific heat
Water Cycle-Reservoirs • Ocean • Atmosphere • Glaciers • Fresh water • Ground water • Living things
Water cycle-Driving force • The sun is the major driving force of the water cycle • Causes evaporation • Causes transpiration • When cooler causes precipitation
Water cycle-Human Effect • Withdraw large amounts of water • Pollute water • Deforestation (climate change)-Loss of transpiration-less water in atmosphere & increases temperature dries out soil. Creates desert. More carbon dioxide increases global warming.
Description of water cycle • Sun heats water in ocean • Evaporates as vapor into air • Transpiration from trees also add water vapor to atmosphere • Cooler temperatures cause vapor to condense and precipitate • Water returns directly to oceans as precipitation or indirectly by runoff
Carbon Cycle-Why important? • Building blocks of cells-Proteins, Lipids, Carbohydrates, Nucleic acids are carbon based molecules • Carbon and oxygen from carbon dioxide is used to make glucose in photosynthesis
Carbon cycle reservoirs • Atmosphere in the form of inorganic carbon dioxide • Carbon dioxide dissolved in oceans • Living things in form of organic molecules • Underground-fossil fuels • Rocks-limestone (calcium carbonate)
Carbon cycle driving force • Photosynthesis captures inorganic carbon in form of carbon dioxide and converts it to organic molecules (glucose) • Cell respiration returns carbon dioxide to abiotic
Carbon cycle-Human effect • Humans are adding excess carbon dioxide to atmosphere through burning of fossil fuels and deforestation (loss of carbon dioxide removal)
Carbon cycle description • Carbon dioxide is captured by plants and converted into organic molecules by photosynthesis • Consumers eat plant and carbon ids transferred • Organism die and decomposers break organic molecules back to carbon dioxide and released back to air • Cell respiration also returns carbon dioxide back to air. • Burning fossil fuels & volcanoes increase carbon dioxide in air
Nitrogen Cycle-Why important • Important in making nucleic acids, ATP, and Amino acids
Nitrogen Cycle-Reservoir • Atmosphere is 75% free nitrogen
Nitrogen Cycle driving force • Bacteria • Nitrogen fixing bacteria capture free nitrogen from air and convert it to ammonia • Nitrifying bacteria-convert ammonium to nitrates and nitrites • Denitrifying bacteria convert nitritrites back to free nitrogen • Ammonifying bacteria convert organic molecules to ammonium
Nitrogen Cycle-human effect • Fertilizers contain large amounts of nitrogen-run off in stream create eutrophication • Nitrogen released into air by factories combine with water to form nitric acid-acid rain • Farming depletes soil of nitrogen
Nitrogen cycle description • Free atmospheric nitrogen is converted by nitrogen fixing bacteria found in soil and root nodules of legumes to ammonia • Plants can use ammonia but ammonia is usually converted to nitrates and nitrites by nitrifying bacteria which plants take up • Consumers eat plants • Organisms die and ammonifying bacteria convert back to ammonia which can be nitrified and reused or denitrified by denitrifying bacteria to free nitrogen again.
