biol270chap_7C - Chapter 7 Chapter 7 Water Hydrologic Cycle...

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Unformatted text preview: Chapter 7 Chapter 7 Water: Hydrologic Cycle and Human Use 1989 2003 ? What Happened? Similar stories Similar stories Dead Sea Rio Grande River Colorado River Water: A Vital Resource Water: A Vital Resource Temperature determines whether Temperature determines whether water is a Gas: water vapor Liquid: running water Solid: ice The Water Cycle The Water Cycle Precipitation Precipitation Relative humidity­ the amount of water vapor in the air, relative to the amount that can be held at that temperature. Warm air hold more water than cold air. Warm air rises, expands and cools 100% relative humidity = clouds Increasing condensation = water droplets Evapo­transpiration Evapo­transpiration Global Air Circulation Global Air Circulation Global Precipitation Global Precipitation Global Precipitation Global Precipitation Global precipitation distribution depends on patterns of rising and falling air currents Two main factors: global convection currents rain shadow effect Rain Shadow Effect Rain Shadow Effect The Water Cycle (groundwater) The Water Cycle (groundwater) Loss of ecosystem services Human Impacts on the Water Human Impacts on the Water Cycle What drives crayfish biodiversity in a big river What drives crayfish biodiversity in a big river floodplain: Dispersal during flood pulse 1) Random distribution 2) Spatial autocorrelation 3) Landscape patch dynamics Does production vary across Does production vary across landscape patches? Examine production of eastern red swamp crayfish across a dynamic floodplain landscape Falling water tables Diminishing surface waters (wetlands) Land subsidence Saltwater intrusion Consequences of Overdrawing Consequences of Overdrawing Groundwater Center Pivot Irrigation Center Pivot Irrigation 10,000 gallons/minute Aerial View of Center Pivot Aerial View of Center Pivot Irrigation Sites Sinkhole Sinkhole Saltwater Intrusion Saltwater Intrusion Water Stewardship: Public­Policy Water Stewardship: Public­Policy Challenges Obtaining more water More dams (Three Gorges Dam) Tapping more groundwater Desalting seawater Using less water Public­policy challenges Dams: Disrupt Integrity of River Dams: Disrupt Integrity of River System Above the dam Flooding Sediment deposition Loss of functional flood plain Loss of normal river flow patterns Loss of river biota Loss of functional floodplain Below the dam Desalting Seawater Desalting Seawater Reverse osmosis Distillation Using Less Water Using Less Water Irrigation Surge flow Drip irrigation $$$$ Municipal uses Incentives and regulations limiting water use Gray water National Water Policy National Water Policy Promote water efficiency Reduce or eliminate water subsidies Charge polluters Add watershed management to pricing of water Chapter 8 Chapter 8 Soil: Foundation for Land Ecosystems Why a Study of Soil Is Important Why a Study of Soil Is Important 90% of the world’s food comes from land­ based agriculture. Maintenance of soil is the cornerstone of sustainable civilizations. Simply stated, it is the “foundation” of terrestrial life. Topsoil Formation Topsoil Formation Soil Profile Soil Profile Soil Texture Soil Texture Soil texture: the percentage of sand, silt, and clay particles found in the soil. Sand Silt Clay Large Small Smaller Soil Texture Triangle Soil Texture Triangle Soil Classification Soil Classification Order, suborder, groups, subgroup, family, etc. Main soil orders Mollisols: fertile soils with deep A horizon; best agriculture soils Oxisols: iron and aluminum oxides in B horizon; little O horizon; Poor agriculture soils Main soil orders continued Main soil orders continued Alfisols: well­developed O, A, E, and B horizons; suitable for agriculture if supplemented Aridisols: little vertical structure; thin and unsuitable for sustainable agriculture Plant­soil­water Relationships Plant­soil­water Relationships Water Transport by Transpiration Water Transport by Transpiration ...
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