LE 54-4Open oceanContinental shelfUpwelling zonesExtreme desert, rock, sand, iceSwamp and marshLake and streamDesert and semidesert scrubTropical rain forestTemperate deciduous forestTemperate evergreen forestTropical seasonal forestSavannaCultivated landEstuaryAlgal beds and reefsBoreal forest (taiga)Temperate grasslandWoodland and shrublandTundra0.40.41.01.184.108.40.206.220.127.116.11.18.104.22.168.10.15.265.0Freshwater (on continents)TerrestrialMarineKey Percentage of Earth’ssurface areaAverage net primaryproduction (g/m2/yr)6050403020100 2,5002,0001,5001,0005000Percentage of Earth’s netprimary production25201510501252,5003601,5005003.0909006008002,2006002501,6001,2001,3002,0007001400.37.99.19.22.214.171.124.126.96.36.199188.8.131.52.90.10.040.922
LE 54-12aTrophic level Dry weight(g/m2)Tertiary consumersSecondary consumersPrimary consumersPrimary producers1.51137809Most biomass pyramids show a sharp decrease in biomass atsuccessively higher trophic levels, as illustrated by data from abog at Silver Springs, Florida.
LE 54-12bTrophic level Dry weight(g/m2)Primary consumers (zooplankton)Primary producers (phytoplankton)214In some aquatic ecosystems, such as the English Channel, a smallstanding crop of primary producers (phytoplankton) supports a largerstanding crop of primary consumers (zooplankton).
In a bluegrass field in Michigan, only 3 top carnivores aresupported in an ecosystem based on production by nearly 6million plantsTrophic level Number ofindividual organismsTertiary consumersSecondary consumersPrimary consumersPrimary producers3354,904708,6245,842,424
LE 54-19Concrete dams and weirsbuilt across streams at thebottom of watershedsenabled researchers tomonitor the outflow ofwater and nutrients fromthe ecosystem.One watershed was clear cut to study the effects of the lossof vegetation on drainage and nutrient cycling.The concentration of nitrate in runoff from the deforested watershed was 60 times greaterthan in a control (unlogged) watershed.DeforestedControlCompletion oftree cuttingNitrateconcentrationinrunoff(mg/L)1965 19681966 196780.060.040.020.04.03.02.01.00