ecosystems: what are they and how do they work? chapter 3 sections 5-7
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Ecosystems: What Are Ecosystems: What Are They and How Do They They and How Do They
Work?Work?
Chapter 3Chapter 3
Sections 5-7Sections 5-7
Importance of SoilsImportance of Soils Provides nutrients for plant growth (Base of Provides nutrients for plant growth (Base of
life on land)life on land)
Water Cleansing & StorageWater Cleansing & Storage
Helps decompose & recycle wasteHelps decompose & recycle waste
Potentially renewable resourcePotentially renewable resource(1 cm of soil requires 15yrs to several hundred years to form)(1 cm of soil requires 15yrs to several hundred years to form)
Climate Control - COClimate Control - CO22 storage storage
Soil HorizonsSoil Horizons
O Horizon = surface litter - O Horizon = surface litter - Brown or BlackBrown or Black Non-Non-decomposed leaves, twigs, crop & animal waste, fungi , decomposed leaves, twigs, crop & animal waste, fungi ,
A Horizon = A Horizon = Topsoil - Dark & LooseTopsoil - Dark & Looseporous mixture of partially decomposed porous mixture of partially decomposed humushumus, and inorganic minerals, and inorganic minerals
B Horizon = subsoilB Horizon = subsoil
C Horizon = C Horizon = Parent MaterialParent Material
Oak tree
Woodsorrel
Lords andladies
EarthwormDog violet
MoleMillipede
Honeyfungus
Organic debrisbuilds up
Moss andlichen
Rockfragments
Bedrock
Immature soil
Regolith
Young soil
PseudoscorpionMite
Nematode
Actinomycetes
FungusBacteria
SpringtailRed earthmite
Mature soil
Root system
C horizonParent material
B horizonSubsoil
A horizonTopsoil
Grasses andsmall shrubs
Fern
Fig. 3-21, p. 51
Soil Formation and HorizonsSoil Formation and Horizons
O horizonLeaf litter
Fig. 3-22, p. 52
Soil Profiles Soil Profiles from Different from Different
EcosystemsEcosystems
Gray,
Gray, yellow & red topsoils are low in organic matter
& need N to support crops
Soil profiles interaction
AnimationAnimation
pHpH
Acidity or alkalinity of water or water-bearing samplesAcidity or alkalinity of water or water-bearing samples
Scale 0-14Scale 0-14
Acidic: pH 0-6.9Acidic: pH 0-6.9
Neutral pH 7.0Neutral pH 7.0
Alkaline (basic): pH 7.1-14Alkaline (basic): pH 7.1-14
The pH ScaleThe pH Scale
Fig. 3-23, p. 192
Matter Cycling in Ecosystems: Matter Cycling in Ecosystems: Biogeochemical CyclesBiogeochemical Cycles
Nutrient (biogeochemical) cyclesNutrient (biogeochemical) cycles
Hydrologic (water) cycleHydrologic (water) cycle
Carbon cycleCarbon cycle
Nitrogen cycleNitrogen cycle
Phosphorus cyclePhosphorus cycle
Sulfur cycleSulfur cycle
PrecipitationPrecipitation
to land
Evaporation
EvaporationFromocean
Ocean storage
Condensation
Transpiration
Rain clouds
Infiltration andpercolation
Transpirationfrom plants
Groundwater movement (slow)
Precipitation
Simplified Hydrologic (Water) CycleSimplified Hydrologic (Water) Cycle
Fig. 3-24, p. 54
Surface runoff (rapid)
EvaporationFromocean
Rapid Precipitationto ocean
Surface runoff (rapid)
Water cycle interaction
AnimationAnimation
Human Interventions in the Human Interventions in the Hydrologic CycleHydrologic Cycle
1.1. Large withdraw of surface and ground watersLarge withdraw of surface and ground waters
2.2. Clearing vegetation / wetland destructionClearing vegetation / wetland destruction - - runoff, runoff, infiltration, infiltration, groundwater recharge, groundwater recharge, flood risk, flood risk, soil soil erosion & landslideserosion & landslides
3.3. PollutionPollution - addition of nutrients - addition of nutrients
Diffusion betweenatmosphere and ocean
Carbon dioxidedissolved inocean water
Marine food websProducers, consumers,
decomposers, detritivores
Marine sediments, includingformations with fossil fuels
Combustion of fossil fuels
Fig. 3-25a, p. 56
The Carbon Cycle (Marine)The Carbon Cycle (Marine)
sedimentation
uplifting over geologic time
photosynthesis aerobic respiration
death, sedimentation
incorporation into sediments
Atmosphere(most carbon is in carbon dioxide)
Terrestrialrocks
Land food websProducers, consumers,
decomposers, detritivores
Peat,fossil fuels
Soil water(dissolved carbon)
Combustionof fossil
fuelsvolcanic action
Fig. 3-25b, p. 57
The Carbon Cycle (Terrestrial)The Carbon Cycle (Terrestrial)
photosynthesis
death, burial, compaction over geologic time
aerobic respiration
deforestaion
combustion of wood (for clearing
land; or fuel)
weathering
leaching, runoff
Carbon cycle animation- LEARN THE CARBON CYCLE!
AnimationAnimation
Fig. 3-26, p. 56
Highprojection
Lowprojection
Human Interferences in the Human Interferences in the Global Carbon CycleGlobal Carbon Cycle
1. Clearing Vegetation
2. Burning Fossil Fuels
potential consequences?
Gaseous Nitrogen (N2)in AtmosphereNitrogen
Fixationby industry
for agricultureFood Webs
on Land
Fertilizersuptake byautotrophs
excretion, death,decomposition
uptake byautotrophs
Nitrogenous Wastes,Remains in Soil
NO3–
in Soil
NO2–
in Soilloss by
leaching
1. Nitrificationbacteria convert NH4
+
to nitrite (NO2–)
2. Nitrificationbacteria convert NO2
–
to nitrate (NO3–)
Ammonificationbacteria, fungi convert the
residues to NH3; thisdissolves to form NH4
+
NH3, NH4+
in Soil
loss byleaching
Nitrogen Fixationbacteria convert N2 toammonia (NH3); this
dissolves to formammonium (NH4
+)
Denitrificationby bacteria
Fig. 3-27, p. 58
The Nitrogen CycleThe Nitrogen Cycle
Nitrogen cycle interaction - LEARN THE NITROGEN CYCLE!(Animations on School Server)
AnimationAnimation
Human Interferences in the Human Interferences in the Global Nitrogen CycleGlobal Nitrogen Cycle1.Add nitric oxide (NO) to atmosphere -
can form acid rain2.Add nitrous oxide N2O to atmosphere via
anaerobic decomposition & inorganic fertilizers - greenhouse gas
3.Nitrate in inorganic fertilizers can leach thru soil & contaminate groundwater
4.Release large quantities of N into troposphere via habitat destruction
5.Upset aquatic ecosystems from excess nitrates in ag. runoff & sewage- eutrophication
Marine Sediments Rocks
Marine Food Webs
Dissolvedin Ocean
Water
Dissolvedin Soil Water,Lakes, Rivers
LandFoodWebs
Guano
Fertilizer
excretion
uptake byautotrophs
death,decomposition
sedimentation settling outuplifting overgeologic time
weathering
uptake byautotrophs
weathering
mining
leaching, runoff
agriculture
Fig. 3-29, p. 59
The Phosphorus CycleThe Phosphorus Cycle
Phosphorus cycle animation
AnimationAnimation
Human Interventions in the Human Interventions in the Phosphorus CyclePhosphorus Cycle
1. Mining of phosphate rock
2. Clearing tropical forests reduces available phosphate in tropical soils
3. Phosphates from runoff of animal wastes, sewage & fertilizers disrupts aquatic ecosystems - eutrophication
“Since 1900, human activities have increased the natural rate of phosphorous release to environment by about 3.7 fold”
Ocean
Hydrogen sulfide
Industries
Volcano
Oxygen
Water AmmoniaSulfur trioxide Sulfuric acid Acidic fog and precipitation
Ammonium sulfate
Plants
Animals
Sulfate salts
Hydrogen sulfide
SulfurDecaying matterMetallicSulfidedeposits
Dimethyl sulfide
Sulfur dioxide
Fig. 3-30, p. 60
The Sulfur CycleThe Sulfur Cycle
Sulfur cycle animation
AnimationAnimation
How Do Ecologists Learn How Do Ecologists Learn about Ecosystems?about Ecosystems?
Field researchField research
Remote sensingRemote sensing
Geographic information system (GIS)Geographic information system (GIS)
Laboratory researchLaboratory research
Systems analysisSystems analysis
Fig. 3-31, p. 61
Wetland Lake
Critical nesting site locations
USDA Forest Service
Topography
Habitat type
Real world
Privateowner 1
Private owner 2
USDAForest Service
Grassland
Forest
Geographic Information System (GIS)Geographic Information System (GIS)
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