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BGC-day 1. Water, Carbon, and Phosphorus Biogeochemical Cycles. Essential Elements. C, N, P, K, Mg, Ca, S “C ycle” through trophic levels Producers obtain them from the atmosphere or dissolved as ions in water Consumers eat producers
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BGC-day 1 Water, Carbon, and Phosphorus Biogeochemical Cycles
Essential Elements • C, N, P, K, Mg, Ca, S “Cycle” through trophic levels • Producers obtain them from the atmosphere or dissolved as ions in water • Consumers eat producers • Decomposers break down complex forms and create simple forms useable again by producers
Nutrient Budgets • Inorganic --> organic --> inorganic • Atm <--> land <--> water • Inputs (sources) • Outputs (sinks) • Pathways • KNOW HUMAN IMPACTS on each BGC cycle
Hydrologic Cycle • Water is essential to living organisms • Dissolves/transports essential element • Precipitation • Evaporation • Transpiration • Evapotranspiration • Infiltration/percolation • runoff
Human Impacts-water • Dams: water supply & flood control • Pavement-impervious surfaces • Air Pollutant: Aerosols • light scattering, brighter clouds • less sunlight reaching surface so less NRG to drive the cycle!
Carbon Cycle • 20% by weight • Backbone for long chains of organic molecules • SIX Processes: • Photosynthesis • Respiration • Exchange • Sedimentation and burial • Extraction • Combustion
Carbon Cycle • Fast part: within living organisms
Carbon Cycle • Slow part: rocks & soils, hydrocarbons • CO2into oceans CaCO3(ppt) = limestone & dolomite rock • Fossilized C Petroleum • EXTRACTION of fossil fuels by humans causes COMBUSTION
Carbon Storage • marine sediments & sedimentary rocks (organisms shells (diatoms)) • Oceans • Fossil Fuels • Soil Organic matter • Forests
Human Impacts-Carbon Cycle • w/o humans: • Earth/atmosphere C exchange is a steady state (entering = leaving): 10,000 yrs • Industrial Revolution • Excess CO2 in atmosphere: Global warming • Tree harvesting • C storage in wood • Cutting/Burning • pastures, croplands, grasslands
Human Impacts-Net Carbon Release • Deforestation • Combustion since Industrial Revolution • Fossil Fuels: especially coal • Burning wood: cooking, heating
Phosphorus Cycle • no atmospheric component • no bacterial role • Land <-->sediments • Limiting factor in freshwater aquatic systems • Source: Rocks: PO43- • Sink: Ocean (Aquatic) sediments
P in Living Organisms • Taken up by plants & moves up the system • ATP & nucleic acids(DNA/RNA & ATP) • decomposers
P Loss/Return • runoff to oceans • Guano
Human Impacts-P • mining for fertilizers-Speed up the long term loss from land • runoff- feedlots, fertilizers • sewage discharge • clearcutting, agriculture, residential-land uses-P not stored in vegetation • Inorganic fertilizer use • ***Cultural Eutrophication
Lake Washington • post WWII suburbanization • 10 STP’s, 20 million gallons/day • primary treatment only for bacteria • cultural eutrophication • Oscillatoria blooms
NO3- • Top: just N • NO3-& PO4-3