Presentation on theme: "Earth Systems and Resources – College Board"— Presentation transcript:
1Earth Systems and Resources – College Board C. Global water resources and use:Freshwater/saltwaterOcean circulationAgricultural (use)Industrial and domestic useSurface and groundwater issuesGlobal problemsConservation
5Properties of WaterHydrogen bonding - creates properties of water that enable life to existHigh heat capacityHigh heat of vaporizationExpands as it freezesUniversal solventAdhesive/cohesive
6Properties of Water High heat capacity Changes temperature slowlyUneven heating/cooling creates winds, currentsModerates climateCold places are warmer, warm places are coolerHigh heat of Vaporization – as water evaporates, it removes heatEvaporative cooling
7Universal Solvent Water can dissolve a lot of compounds Nitrates, K, Ca, glucose making them available to cellsIt can easily become polluted by water-soluble wastes
8Properties of Water Expands as it freezes Most dense at 4oC Ice forms at the surfaceUpwelling - cooler water rises to the surface, bringing nutrients into the photic zoneTurnover
9Thermal Stratification In summer, the surface water is warm - less dense (lighter)Thermocline - middle layer prevents the transfer of nutrients from the bottom and dissolved oxygen from the topOxygen dissolves into water at the surfacePoop and dead stuff floats to the bottom – nitrogen cycle
10Fall Turnover Temperature begins to fall Surface layer becomes more denseSinks to the bottomNutrients circulate to the surface and oxygen to the bottomUpwellingWinter – layers are fairly even
11Spring Turnover Ice melts; cold water warms up Sinks below the cooler (less dense) waterOxygen circulates down and nutrients (nitrates) circulate to top (photic)
12Aquatic Life Zones Abiotic factors determine who lives where: SunlightSalinityTurbidityTemperatureDissolved oxygenTwo aquatic biomes – fresh and marine
13Marine Biomes – 71 % of Earth Economic benefits:FoodOil, natural gas, mineralsTransportationRecreationEcological benefits:Moderates climateHabitat and nursery areasAbsorbs CO2 (CaCO3)Reduces storm impact
15Coastal BiomeHigh tide to continental shelf90% of all marine life
16Estuary Where the river meets the oceans Bays, inlets, sounds, salt marshes, mangrove swampsHighly productive (1o productivity)Nutrient-rich nurseriesFilter toxinsPrevent beach erosion
17Coastal Zones Salt marsh - nursery for many fish Lots of 1o production Prevent beach erosionFilters toxinsIntertidal zone – between high and low tidesCoral reef - slow growing coral animals build reefsMutualism with zooxanthellae algaeClose to surface
26Peat Moss BogA wet area that over time fills in (the last stage of succession is peat moss).Can be very deep.May be burned as fuel.
27Water CycleRunoff - water that does not sink into the ground or evaporateWatershed or drainage basin - the land that drains water into a lake or river
28Surface WaterCan be flowing (rivers/streams) or standing (lakes, ponds, wetlands)Source – precipitationWatershed – Ex. small streams larger streams rivers sea
29Rivers and Streams Deliver nutrients to sea Deposit silt that maintains deltasPurify waterRenew and renourish wetlandsProvide habitats for wildlife
30Headwaters Cold, clear water; waterfalls and rapids High amounts of dissolved oxygen (DO)Oxygen diffuses into water at the surfaceMany headwaters form a stream/river
31Downstream Characteristics Waters spread out, move more slowly, warmer temperatures, less DOAlgae and cyanobacteriaLittoral zone grows more emergent plants
32FreshwaterGroundwater - precipitation that penetrates (percolates) the ground and is stored underground (aquifer)Aquifers–porous rock w/ water flowing throughWater Table – the level of earth’s land crust to which the aquifer is filledRenewability – the circulation rate of groundwater is slow (300 to 4,600 years).
33Water Usage Irrigation Industry – coolant (power plant) Domestic and MunicipalWe currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025Irrigation = 70%; Industries = 20%; Cities and residences = 10%About 70% of the water is not returned to the sources
34RestorationBuild huge aqueduct, or find other sources of fresh water and protect it federally under endangered species act, etc.
35FloodingHeavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.Floodplains, which usually include highly productive wetlands, help provide natural flood and erosion control, maintain high water quality, and recharge groundwater.To minimize floods, rivers have been narrowed with levees and walls, and dammed to store water.
36Oxygen released by vegetation Diverse ecological habitatEvapotranspirationTrees reduce soil erosion from heavy rain and windAgricultural landSteady river flowLeaf litter improves soil fertilityFigure 14.23Natural capital degradation: hillside before and after deforestation. Once a hillside has been deforested for timber and fuelwood, livestock grazing, or unsustainable farming, water from precipitation rushes down the denuded slopes, erodes precious topsoil, and can increase flooding in local streams. Such deforestation can also increase landslides and mudflows. A 3,000-year-old Chinese proverb says, “To protect your rivers, protect your mountains.”Tree roots stabilize soil and aid water flowVegetation releases water slowly and reduces flooding
37Evapotranspiration decreases Roads destabilize hillsides After DeforestationTree plantationEvapotranspiration decreasesRoads destabilize hillsidesRanching accelerates soil erosion by water and windWinds remove fragile topsoilGullies and landslidesAgricultural land is flooded and silted upFigure 14.23Natural capital degradation: hillside before and after deforestation. Once a hillside has been deforested for timber and fuelwood, livestock grazing, or unsustainable farming, water from precipitation rushes down the denuded slopes, erodes precious topsoil, and can increase flooding in local streams. Such deforestation can also increase landslides and mudflows. A 3,000-year-old Chinese proverb says, “To protect your rivers, protect your mountains.”Heavy rain leaches nutrients from soil and erodes topsoilRapid runoff causes floodingSilt from erosion blocks rivers and reservoirs and causes flooding downstreamFig b, p. 330
38Too Little Water Drought Desertification Lake levels drop, recreation use drops, fisheries drop, and salinization occursEx. Soviet Union (Aral Sea); the inland sea drained the river that fed into it.
39Water was diverted (irrigation) from the Aral Sea and its two feeder rivers About 85% of the wetlands have been eliminated and roughly 50% of the local bird and mammal species have disappeared.Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters most likely causing 20 of the 24 native fish species to go extinct.
40Salinization of Irrigated Soil Water is poured onto soil and evaporates. Over time, as this is repeated, nothing will grow there anymore.