Lecture 2:Environmental Systems:Dynamic change and glow across interfaces; cyclingVariation in time and space (temporal and spatial scales)Flows across interfaces and scalesZones of abrupt change at difference spatial scalesMolecular-Cellular-organismSize- viruses, mite, salmon, trees, forests, earthInterfaces/boundariesFeedback systems: controlling system balance and stabilityNegative Feedback- system is stabilized by counteracting response to perturbationE.g.: sweating- countering something that could be harmfulPositive Feedback: an accelerating process in the same direction, reinforced feedback, tends to destabilize a systemMethane- fossil fuel used for heating/energy- trapped methane in ice, bubbles up as arctic ocean warms (warming leads to more warming)Methane hydrate-based ecosystem on Ocean floorLecture 3: September 7, 2011Science of the EnvironmentHolistic, multi-disciplinary, direct applications to human-nature relationships (policy & ethics)IT HAS A HUMAN DIMENSIONIn the past it was viewed as “descriptive/ value-laden” opinionatedEmpirical InvestigationsObservation + experimentation > data collection > hypothesis or idea or generalizationREASONING: (from specific to general)Predicting system behavior or a cause effect relationship, often with “if…then” statementDEDUCTIVE REASONING: (go from general idea to specific)Nature of a good hypothesisSome basis in current scientific understanding (logical, clear, concise)Can test with observations or experimentsFrom scientist’s ideas world view, observed patterns in natureIF IT SURVIVES MANY ATTEMPTS TO FALSIFY with observation and experimentation, then it becomes “provisionally accepted.” Can lead to a “THEORY” – a well-tested explanation (aren’t weak)Leads to proof with absolute certainty (importance of reproducibility, probability, statistics)What are implications for environmental policy (made in the face of scientific uncertainty)The Dead Flashlight: science in actionSources of “uncertainty”Precision –reproducibility of replicated dataHigh precision- if values are close to one another“standard deviation”low precision- poor reproducibility , values are not close to one anotherAccuracy is not the same a precision!Accuracy: closeness of measured value to “true value”Measurements could be precise but inaccurateLecture September 9, 2011Cyanobacteria (blue green algae) and Calcite CrystalsThey fix CO2 to sugars (PHOTOSYNTHESIS)The fix N2 to NH4+ (NIROGEN FIXATION)They form CaCO3 in same environment (MINERAL FORMATION)Two products of photosynthesis: glucose and oxygenLecture 5: September 12, 2011Peat Bog in Sweden: accumulation of organic carbonImplications: C sequestration (accumulation in the land) and climate change“nonrenewable” fuel source (takes a long time to accumulate)wetland protection and biome stabilityPools and FluxNitogen-fixing nodules on soybean rootsNodules= mostly bacteria and leghemoglobin protein (spheres)Enzyme: nitrogenaseSeptember 14, 2011Solar Decathlon on Mall in DCSept 23-October 2Open 10-2 weekdays and 10-5:30 weekendsVisit at least 2 houses, go through and talk to students- write a reflection paper2/3 pagesMarquee LecturesSept 28 is the bay worth savingNov 14 evolution of life5 pm in 1101 Biosciences Res. Bldg.How does agriculture co-opt the carbon cycle?We have enhanceed the kind of carbon that is fixedWhat is lactic acidBuilds up when theres a lack of oxygenThe acid degrades when the oxygen catches up againAn example of a partially degraded carbon compoundWhy is photosynthesis central to energy flows in most ecosystems?Important first step in sun energy transformationWhere does atmospheric oxygen gas come fromBy product of photosynthesisUse both products of photosynthesis in cellular respiration (sugar/ oxygen)Haber Bosch Process: Artificial Nitrogen Fixation(to create fertilizer)Fritz Haber (1868-1934)Process invented (1908): N2(g)+ 3H2 (g) >> 2NH3 (g)Requires 400 degrees C and 200 atm pressure with Fe catalyst in industrial processVERY DIFFERENT FROM BIOLOGICAL ONE, TAKES A LOT OF FOSSIL FUEL- one reason why agriculture is so energy intensiveMajor process for fertilizer production; a major category of energy consumption in conventional agriculture; 50% more N fixed now by humans than by natural processesHe was awarded the Nobel Prize- controversial because he also helped to develop poison gasesIron catalystEnvironmental Implications of NitrificationNitrite is ephemeral in soils and nat’l watersNitrate is persistent; both are solubleConcerns:Methemoglobinemia (blue-baby syndrome)Eutrophication of saline watrs by green algaeCompare with blue-green algae in fresh waterEx: bay- keep nitrates out of the bay/ algae‘Dead zones’- anaerobic bacteria that don’t use oxygenUS drinking water standard: ( to protect babies)10 mg nitrate- N/L (ppm)Lecture September 16, 11Nitrogen fixation: ultimately becomes protein , important for humansForaminifera: very small, tiny shells that formEnvironmental Implications of Denitirification“good” in that nitrate>> gas; wastewater or groundwater “cleaned” (environmental engineer)“bad” in that nitrogen is lost from soil (e.g., from agricultural use by crops) (farmer)N20 is a greenhouse gas (absorbs infrared (IR) radiation from earth)Occurs in wetlands, poorly-drained soils, swamps and tidal marshesBiomes or Ecoregions; Global Ecological CommunitiesFundamental Observation:Similar ecosystems are found under similar conditions of ….Latitude (N &S of equator)Continental position (relative to seas and oceans)Elevation (above sea level)Climate, topography, and soil conditions determine plant community characterEcoregions of the ContinentsMediterranean chaparral regions: 30-45 degrees N & S latitudeWestern side of continental land massesLow elevationWet winters and dry summersTEMPERATURE AND PRECIPITATION: DETERMINANTS OF BIOME DISTRIBUTIONAral Sea Disaster1960: 4TH largest lake on earth; fisheries importantirrigated cotton in Soviet era- 2 rivers now do not reach the Aral (diversions took the water)poster child of environmental disasternew desert; salt beds; lake may disappear, polluted water and toxic dust but….a huge environmental restoration processFundamental Energy for EarthEnergy sources: solar, kinetic, and internal corePoles: 40% as much solar energy as equatorHeat transfer: equator to polesMacroclimates would be in latitudinal bands determined by solar radiationGeneralized zones for plant growth determined