nutrient cycles in ecosystems. biogeochemical cycle the flow of a nutrient from the environment to...
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Biogeochemical CycleBiogeochemical Cycle
The flow of a nutrient from the The flow of a nutrient from the
environment to living organisms environment to living organisms
and back to the environmentand back to the environment
Main reservoir for the nutrient Main reservoir for the nutrient
is in the environmentis in the environment
geochemical cycleMain nutrient reservoirs in the
environment
fraction of nutrient
available to ecosystem
primary producers
herbivores, carnivores, parasites
detritivores, decomposers
Fig. 47-14, p.852
Three CategoriesThree Categories
Hydrologic cycleHydrologic cycle WaterWater
Atmospheric cycles Atmospheric cycles Nitrogen and carbonNitrogen and carbon
Sedimentary cycles Sedimentary cycles Phosphorus and sulfurPhosphorus and sulfur
Hydrologic CycleHydrologic CycleAtmosphere
Ocean Land
evaporation from ocean
425,000
precipitation into ocean 385,000
evaporation from land plants (evapotranspiration)
71,000
precipitation onto land 111,000
wind-driven water vapor40,000
surface and groundwater flow 40,000
Figure 47-15Page 853
EVAPORATION PRECIPITATION TRANSPIRATION
dripping, tricklingdown along stems
falling throughto ground
interception by plants
surface pooling, etc.
infiltration of soil
moisture in soil
seepage, percolation
groundwater storage
DEEP OUTFLOW
overland flow
lateral flow
base flow
STREAM OUTFLOW
Fig. 47-16, p.853
Water Use and ScarcityWater Use and Scarcity
Most of Earth’s water is too Most of Earth’s water is too
salty for human consumptionsalty for human consumption
Desalinization is expensive Desalinization is expensive
and requires large energy and requires large energy
inputsinputs
Irrigation of crops is the main use of Irrigation of crops is the main use of
freshwaterfreshwater
Negative Effects of IrrigationNegative Effects of Irrigation
Salinization, mineral buildup in soilSalinization, mineral buildup in soil
Elevation of the water table and Elevation of the water table and
waterloggingwaterlogging
Depletion of aquifersDepletion of aquifers
Carbon CycleCarbon Cycle
Carbon moves through the Carbon moves through the
atmosphere and food webs on its atmosphere and food webs on its
way to and from the ocean, way to and from the ocean,
sediments, and rockssediments, and rocks
Sediments and rocks are the main Sediments and rocks are the main
reservoirreservoir
Figure 47-20 Page 856
diffusion between atmosphere and ocean
bicarbonate and carbonate in ocean water
marine food webs
marine sediments
combustion of fossil fuels
incorporation into sediments
death, sedimentation uplifting
sedimentation
photosynthesis aerobic respiration
Carbon Cycle - MarineCarbon Cycle - Marine
Carbon Cycle - LandCarbon Cycle - Land
photosynthesis aerobic respirationterrestrial
rocks
soil water
land food webs
atmosphere
peat, fossil fuels
combustion of wood
sedimentation
volcanic action
death, burial, compaction over geologic time
leaching, runoff
weathering
combustion of fossil fuels
Figure 47-20 Page 856
Carbon in the OceansCarbon in the Oceans
Most carbon in the ocean is dissolved Most carbon in the ocean is dissolved carbonate and bicarbonatecarbonate and bicarbonate
Ocean currents carry dissolved carbon Ocean currents carry dissolved carbon
Carbon in AtmosphereCarbon in Atmosphere
Atmospheric carbon is mainly carbon Atmospheric carbon is mainly carbon dioxidedioxide
Carbon dioxide is added to atmosphereCarbon dioxide is added to atmosphere Aerobic respiration, volcanic action, burning Aerobic respiration, volcanic action, burning
fossil fuels fossil fuels
Removed by photosynthesisRemoved by photosynthesis
Nitrogen CycleNitrogen Cycle
Nitrogen is used in amino acids and Nitrogen is used in amino acids and
nucleic acidsnucleic acids
Main reservoir is nitrogen gas in the Main reservoir is nitrogen gas in the
atmosphereatmosphere
Nitrogen CycleNitrogen Cyclegaseous nitrogen (N2)
in atmosphere
NO3-
in soil
nitrogen fixationby industry
fertilizers
NH3-,NH4
+
in soil
1. Nitrification leaching
uptake by autotrophs
excretion, death, decomposition
uptake by autotrophs
nitrogen fixation
leaching
ammonification 2. Nitrification
dentrification nitrogenous
wastes, remains
NO2-
in soil
food webs on land
Figure 47-25Page 860
Nitrogen FixationNitrogen Fixation
Plants cannot use nitrogen gasPlants cannot use nitrogen gas
Nitrogen-fixing bacteria convert Nitrogen-fixing bacteria convert
nitrogen gas into ammonia (NHnitrogen gas into ammonia (NH33))
Ammonia and ammonium can be Ammonia and ammonium can be
taken up by plantstaken up by plants
Ammonification & NitrificationAmmonification & Nitrification
Bacteria and fungi carry out Bacteria and fungi carry out
ammonificationammonification
conversion of nitrogenous wastes to ammoniaconversion of nitrogenous wastes to ammonia
Nitrifying bacteria convert ammonium to Nitrifying bacteria convert ammonium to
nitrites and nitratesnitrites and nitrates
Nitrogen LossNitrogen Loss
Nitrogen is often a limiting factor in Nitrogen is often a limiting factor in
ecosystemsecosystems
Nitrogen is lost from soils via leaching and Nitrogen is lost from soils via leaching and
runoff runoff
Denitrifying bacteria convert nitrates and Denitrifying bacteria convert nitrates and
nitrites to nitrogen gasnitrites to nitrogen gas
Human EffectsHuman Effects
Humans increase rate of nitrogen loss by Humans increase rate of nitrogen loss by clearing forests and grasslandsclearing forests and grasslands
Humans increase nitrogen in water and air Humans increase nitrogen in water and air by using fertilizers and by burning fossil by using fertilizers and by burning fossil fuelsfuels
Too much or too little nitrogen can Too much or too little nitrogen can compromise plant healthcompromise plant health
guano
fertilizer
terrestrial rocks
land food webs
dissolved in seawater
marine food webs
marine sediments
excretion
weathering
mining
agricultureuptake by producers
death, decomposition
sedimentation settling out
leaching, runoff
weatheringuplifting over geologic time
dissolved in soil water,
lakes, rivers
uptake by autotrophs
death, decomposition
Phosphorus cycle
Fig. 47-27, p.862
Phosphorus CyclePhosphorus Cycle
Phosphorus is part of Phosphorus is part of
phospholipids and all nucleotidesphospholipids and all nucleotides
It is the most prevalent limiting It is the most prevalent limiting
factor in ecosystems factor in ecosystems
Main reservoir is Earth’s crust; Main reservoir is Earth’s crust;
no gaseous phaseno gaseous phase
Phosphorus CyclePhosphorus Cycle
GUANO
FERTILIZER
TERRESTRIAL ROCKS
LAND FOOD WEBS
DISSOLVED IN OCEAN
WATER
MARINE FOOD WEBS
MARINE SEDIMENTS
excretion
weathering
mining
agricultureuptake
by autotrophs
death, decomposition
sedimentationsettling
out leaching, runoff
weathering
uplifting
over geologic time
DISSOLVED IN SOILWATER,
LAKES, RIVERS
uptake by
autotrophs
death, decomposition
Figure 47-27, Page 862
Human EffectsHuman Effects
In tropical countries, clearing lands for In tropical countries, clearing lands for
agriculture may deplete phosphorus-agriculture may deplete phosphorus-
poor soilspoor soils
In developed countries, phosphorus In developed countries, phosphorus
runoff is causing eutrophication of runoff is causing eutrophication of
waterwayswaterways