Biogeochemical Cycles - 1Class Lecture Goals1. What are systems?2. What are biogeochemical cycles?3. Why are they important?4. What is common about them?5. Carbon and nitrogen cycles6. Focus on the Water Cycle (Monday)

Todays Topic: Did Logging Worsen Floods?State Senate CommitteeWeyerhaeuser Co.State DNRDavid MontgomeryPhil MoteIdeasSystem: WatershedCumulative effectsClimate Change

What is a system?System: a collection of matter, parts, or components which are included inside a specified, often arbitrary, boundary. Example: EcosystemSystems often have inputs and outputs.For dynamic systems, by definition, one or more aspects of the system change with time.Example of a simple dynamic system: bathtub or your bank account.The boundary of a dynamic system is chosen for convenient conceptual separation for the system Flux

Night

Reading Assignments Examine this web page (http://www.cses.washington.edu/cig/pnwc/cc.shtml)

Select the true statement from below for the PNW: Climate change willIncrease precipitation & snowpackIncrease temperature & snowpackIncrease precipitation & decrease snowpack

What are biogeochemical cycles?Earth system has four partsAtmosphereHydrosphereLithosphereBiosphereBiogeochemical cycles: The chemical interactions (cycles) that exist between the atmosphere, hydrosphere, lithosphere, and biosphere.Abiotic (physio-chemical) and biotic processes drive these cyclesFocus on carbon and water cycles (but could include all necessary elements for life). N - cycle weakly touched on!

What is common amongst them?Each compound (water, carbon, nitrogen) typically exists in all four parts of the Earth SystemThere are PoolsFluxes in and out of poolsChemical or biochemical transformationsTransformations are importantcan lead to positive & negative consequences

Transformations

5000http://www.epa.gov/climatechange/kids/carbon_cycle_version2.htmlCarbon Cycle

Carbon Cycle DataBurning of fossil fuelsLand conversionCement

Role of OceansRole of terrestrial plants (trees & soils)Lithosphere

Changes in Atmospheric C02 - 1

Changes in Atmospheric C02 - 2

Key Aspects of the Carbon CycleCarbon is the skeleton of all life.Carbon dioxide is a critical gas:Taken up by plants in photosynthesisReleased by plants and animals in respirationReleased during decomposition (and fires)Greenhouse gas (greenhouse effect - your car in the sun)

Question: Photosynthesis is an example of a poolTrueFalse

Nitrogen Cyclehttp://soil.gsfc.nasa.gov/NFTG/nitrocyc.htm

Nitrogen Cyclehttp://soil.gsfc.nasa.gov/NFTG/nitrocyc.htm

Nitrogen Cyclehttp://soil.gsfc.nasa.gov/NFTG/nitrocyc.htm

Nitrogen Sources over time

Nitrogen Cycle: Key PointsNitrogen is in the atmosphere as N2 (78%)N2 is an inert gas and cannot be used by plants or animalsN2 can be converted to a usable form viaLightening N-fixing plants and cyanobacteriaIndustrial process (energy intensive)Nitrogen limits plant growthNitrogen is easily lost from biological systems

Summary1. What are systems?2. What are biogeochemical cycles?3. Why are they important?4. What is common about them?5. Carbon and nitrogen cycles