Lecture 19Lecture 19Regulation of Productivity and Limiting FactorsRegulation of Productivity and Limiting FactorsMarch 21, 2007March 21, 2007Glob aldistrib utionofPrim aryProductivityGlob aldistributionofPrim aryProd uctivityW hatLim itsTerrestrialProd uctivityW hatLim itsTerrestrialProd uctivitylig ht,w ater,tem peraturelig ht,w ater,tem peratureW hoaretheaq uaticPrim aryProducers( theW hoaretheaq uaticPrim aryProducers( theinvisib leforest) ?invisib leforest) ?W hatreg ulatestheirg row th?W hatreg ulatestheirg row th?lig ht,nutrientslig ht,nutrientsLim iting NutrientsLim iting NutrientsTerrestrial Primary ProductionProductivity ranges (g/m2/yr):> 600< 100 100 - 600NASA satellite imageLimits to terrestrial productivityDistribution of primary production, standing biomass, and radiationinput relative to rainfall and temperatureP = Primary Production (tn/ha)B = Biomass (tn/ha)R = Solar Radiation (kcal/m2/yr)How will global climate changeHow will global climate changeinfluence these boundariesinfluence these boundaries?Source: Smith, 2001.Mean Annual Precipitation cmMean Annual Temperature °CMarine Primary ProductionProductivity ranges (g/m2/yr):> 90< 40 40 - 90Higher in Zones of UpwellingNASA satellite imagePhytoplankton: A tourPhytoplankton: A tour• Over 20,000 species• Occur wherever there is water• Range from 0.5 to 1000 µm in diameter• There is as much genetic information in aliter of seawater as in the entire humangenomeFrom Round et al 1990 ‘The diatoms’From Round et al 1990 ‘The diatoms’From Canter-Lund & Lund 1996,‘Freshwater Algae’CoccolithophoresFrom Winter & Siesser 1994, ‘Coccolithophores’Cyanobacteria0.5 mmCourtesy D. KarlNN22NN22NHNH44Nitrogen FixationCyanobacteria importnitrogen into theoceans from theatmosphereProchlorococcus• 0.7µm in diameter• smallest and simplest photosynthetic cell• most abundant• “the essence of life”ProchlorococcusProchlorococcusWhat regulates Aquatic Primary Production ?Productivity ranges (g/m2/yr):> 90< 40 40 - 90NASA satellite imageThe Biological PumpThe Biological PumpHH22OODensityDensityNONO22RegeneratedRegeneratedNHNH44, urea,, urea,orgP,orgP,NONO33 , PO , PO44 , ,etc.etc.UpwellingUpwellingMixedMixedLayerLayerDepthDepthSeasonal Temperature & Mixing Cycles in a Temperate LakeDepthDepthTemperatureTemperatureThermocline Develops4ºCFALLVerticalMixingFallOverturnSurface Layers Cooland Sink (Mixing,Nutrient-Rich WatersRise)Fall BloomWINDS4ºCSPRINGWINDSVertical MixingBrings upNutrientsFrom deepwatersSpringOverturnSpring Overturn, SpringBloom (Winds, DeepMixing, Nutrients Mix toSurface, Solar Radiation)0ºC 4ºCWINTERLow Temperatures(Low Mixing, Low SolarRadiation)NoMixingice4ºCSUMMERThermocline(no mixing)SurfaceNutrientDepletionOxygenDepletion(Thermocline, No deepmixing, NutrientDepletion in SurfaceWaters)0ºCSee also Fig. 58.3 See also Fig. 58.3 in textin textCoastalUpwellingOcean Currents and UpwellingWest Wind DriftContinents DeflectOcean CurrentEquatorial UpwellingCO2nutrients: N, P, etcWindupwellingPhytoplankton bloomOCO2O2CoastalUpwellingGlobal Ocean CirculationWest Wind DriftContinents DeflectOcean CurrentEquatorial UpwellingPrevailingEl NinoEl Nino 1997 La Nina 1998NASA/Goddard Space Flight CenterOceanicConveyer BeltZones ofUpwellingZones ofUpwellingZones ofUpwellingZones ofUpwellingDeep Ocean CurrentsCurrentShallow CurrentsShallow Currents Water sinks inN. AtlanticThe Experimental Lakes Area - OntarioControl Lake+ PO4SERIES Fe FertilizationSERIES Fe FertilizationExperiment 2002Experiment 2002Sub-arctic PacificSub-arctic Pacifichttp://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=10793More on this in the last lecture!Take Home MessagesTake Home MessagesLand Land –– water, sunlight, nutrients water, sunlight, nutrientsOcean Ocean –– sunlight and nutrients sunlight and nutrientsBiosynthesis and nutrient regenerationBiosynthesis and nutrient regenerationalong gradientsalong gradientsUpwelling in oceans criticalUpwelling in oceans criticalLimiting factors/Law of the minimum Limiting factors/Law of the minimum ––Redfield RatioRedfield
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