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Ecosystems: What Are They and How Do They Work?

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Presentation on theme: "Ecosystems: What Are They and How Do They Work?"— Presentation transcript:

1 Ecosystems: What Are They and How Do They Work?
Chapter 3 Sections 5-7

2 Importance of Soils Provides nutrients for plant growth (Base of life on land) Water Cleansing & Storage Helps decompose & recycle waste Potentially renewable resource (1 cm of soil requires 15yrs to several hundred years to form) Climate Control - CO2 storage

3 Soil Horizons O Horizon = surface litter - Brown or Black Non-decomposed leaves, twigs, crop & animal waste, fungi , A Horizon = Topsoil - Dark & Loose porous mixture of partially decomposed humus, and inorganic minerals B Horizon = subsoil C Horizon = Parent Material

4 Soil Formation and Horizons
Wood sorrel Oak tree Lords and ladies Dog violet Earthworm Grasses and small shrubs Organic debris builds up Millipede Moss and lichen Rock fragments Mole Fern Honey fungus O horizon Leaf litter A horizon Topsoil B horizon Subsoil Bedrock Immature soil Regolith Young soil Pseudoscorpion C horizon Parent material Mite Nematode Root system Actinomycetes Red earth mite Springtail Fungus Fig. 3-21, p. 51 Mature soil Bacteria

5 Soil Profiles from Different Ecosystems
Gray, Gray, yellow & red topsoils are low in organic matter & need N to support crops Fig. 3-22, p. 52

6 Animation Soil profiles interaction

7 pH Acidity or alkalinity of water or water-bearing samples Scale 0-14
Acidic: pH 0-6.9 Neutral pH 7.0 Alkaline (basic): pH

8 The pH Scale Fig. 3-23, p. 192

9 Matter Cycling in Ecosystems: Biogeochemical Cycles
Nutrient (biogeochemical) cycles Hydrologic (water) cycle Carbon cycle Nitrogen cycle Phosphorus cycle Sulfur cycle

10 Simplified Hydrologic (Water) Cycle
Condensation Rain clouds Transpiration Evaporation Precipitation to land Transpiration from plants Precipitation Precipitation Evaporation From ocean Evaporation From ocean Surface runoff (rapid) Rapid Precipitation to ocean Infiltration and percolation Surface runoff (rapid) Groundwater movement (slow) Ocean storage Fig. 3-24, p. 54

11 Animation Water cycle interaction

12 Human Interventions in the Hydrologic Cycle
Large withdraw of surface and ground waters Clearing vegetation / wetland destruction -  runoff,  infiltration,  groundwater recharge,  flood risk,  soil erosion & landslides Pollution - addition of nutrients

13 The Carbon Cycle (Marine)
Diffusion between atmosphere and ocean Combustion of fossil fuels Carbon dioxide dissolved in ocean water photosynthesis aerobic respiration Marine food webs Producers, consumers, decomposers, detritivores incorporation into sediments death, sedimentation uplifting over geologic time sedimentation Marine sediments, including formations with fossil fuels Fig. 3-25a, p. 56

14 The Carbon Cycle (Terrestrial)
Atmosphere (most carbon is in carbon dioxide) Combustion of fossil fuels volcanic action combustion of wood (for clearing land; or fuel) aerobic respiration Terrestrial rocks photosynthesis deforestaion weathering Land food webs Producers, consumers, decomposers, detritivores Soil water (dissolved carbon) Peat, fossil fuels death, burial, compaction over geologic time leaching, runoff Fig. 3-25b, p. 57

15 Animation Carbon cycle animation- LEARN THE CARBON CYCLE!

16 Human Interferences in the Global Carbon Cycle
High projection Low Clearing Vegetation Burning Fossil Fuels potential consequences? Fig. 3-26, p. 56

17 bacteria, fungi convert the
The Nitrogen Cycle Gaseous Nitrogen (N2) in Atmosphere Nitrogen Fixation by industry for agriculture Food Webs on Land Fertilizers uptake by autotrophs excretion, death, decomposition Nitrogenous Wastes, Remains in Soil NO3– in Soil NO2– loss by leaching 1. Nitrification bacteria convert NH4+ to nitrite (NO2–) 2. Nitrification bacteria convert NO2– to nitrate (NO3–) Ammonification bacteria, fungi convert the residues to NH3; this dissolves to form NH4+ NH3, NH4+ Nitrogen Fixation bacteria convert N2 to ammonia (NH3); this dissolves to form ammonium (NH4+) Denitrification by bacteria Fig. 3-27, p. 58

18 Animation Nitrogen cycle interaction - LEARN THE NITROGEN CYCLE!
(Animations on School Server)

19 Human Interferences in the Global Nitrogen Cycle
Add nitric oxide (NO) to atmosphere - can form acid rain Add nitrous oxide N2O to atmosphere via anaerobic decomposition & inorganic fertilizers - greenhouse gas Nitrate in inorganic fertilizers can leach thru soil & contaminate groundwater Release large quantities of N into troposphere via habitat destruction Upset aquatic ecosystems from excess nitrates in ag. runoff & sewage- eutrophication

20 The Phosphorus Cycle Fig. 3-29, p. 59 Fertilizer Guano Land Dissolved
mining Fertilizer excretion Guano agriculture uptake by autotrophs uptake by autotrophs Dissolved in Ocean Water leaching, runoff Dissolved in Soil Water, Lakes, Rivers Land Food Webs Marine Food Webs death, decomposition weathering weathering sedimentation settling out uplifting over geologic time Marine Sediments Rocks Fig. 3-29, p. 59

21 Animation Phosphorus cycle animation

22 Human Interventions in the Phosphorus Cycle
Mining of phosphate rock Clearing tropical forests reduces available phosphate in tropical soils 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”

23 Acidic fog and precipitation
The Sulfur Cycle Water Ammonia Sulfur trioxide Sulfuric acid Acidic fog and precipitation Ammonium sulfate Oxygen Sulfur dioxide Hydrogen sulfide Plants Volcano Dimethyl sulfide Animals Industries Ocean Sulfate salts Metallic Sulfide deposits Decaying matter Sulfur Hydrogen sulfide Fig. 3-30, p. 60

24 Animation Sulfur cycle animation

25 How Do Ecologists Learn about Ecosystems?
Field research Remote sensing Geographic information system (GIS) Laboratory research Systems analysis

26 Geographic Information System (GIS)
Critical nesting site locations USDA Forest Service USDA Forest Service Private owner 1 Private owner 2 Topography Forest Habitat type Wetland Lake Grassland Real world Fig. 3-31, p. 61

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