Freshwater. Unit 4: Water. Freshwater. Freshwater. Freshwater. Water Cycle. Water Cycle 2/25/2015. Freshwater. Groundwater. Surface Water.

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1 Freshwater Unit 4: Water Freshwater How did the oceans form? What special adaptations do saltwater organisms have? Where does our water come from? How do humans affect the Earth s water? Freshwater Salinity < 0.05 % ~ 2.5 % of earth s water 79 % found as ice in glaciers Only 1 % available for drinking Freshwater Water beneath the surface of earth 20 % of freshwater Water Table Level of water underground Near/at surface in wet regions 100+ m below in dry regions Freshwater Surface Water Freshwater on Earth s surface Found In: Lakes, Rivers, Streams, Wetlands Communities are built near reliable sources of surface water Water Cycle Water Cycle Water is used in many processes of life Water is abundant and renewable Freshwater is scarce Split between sources (ice, ocean, atmosphere, etc.) always changes Water Cycle Evaporation Liquid to gas Byproduct of cell respiration Transpiration Evaporation in plants Through leaves, stem, etc. Both require heat to occur 1

2 Water Cycle Condensation Gas to liquid Creates cloud formation in the atmosphere Precipitation Rain releases water in the form of rain, sleet, snow, etc. Water Cycle Often ends up in ocean, river, etc. Taken up by plants through soil Humans use wells for irrigation Often split into flowing and standing water Standing Slow or no motion Ponds, wetland, etc. Flowing Near-constant motion Rivers, streams, etc. Standing Water Ponds, lakes, etc. Often have few/no nutrients available Inland Sea Very large lake Animals adapted for open-water Ex: Great Lakes Littoral Zone Near shore Plants grow in mud Much of the nutrients are found here Limnetic Zone Away from shore, but generally lit No rooted plants Like open-ocean zone Wetlands Flooded at least part of the year Absorb water to prevent flooding Home for many commercial fish 2

3 Marsh Shallow water with many high grasses Ex: Meadowlands Swamp Shallow water with trees Ex: Bayou Bog Low nutrients and acidic water Often due to secondary succession Rivers and Streams Shape the landscape as they run Most sources in mountains Little life due to cold temps End in ocean or landlocked sea Flood plains are often fertile Estuaries Rivers flow into sea Brackish water Organisms tolerate high range of salinity High production due to nutrient collection Salt Marsh Stabilize shoreline Rivers leave mineralrich mud Many animals grow to adulthood before going out to sea Ex: Chesapeake Bay Mangrove Forest Tropical regions Mangrove trees grow out to receive oxygen Protect shoreline from erosion Ex: Everglades Watershed Area of land where water drains to same place Also called drainage basin Often contains many tributaries Ex: Mississippi River watershed (1.2 million sq. miles) Watersheds 3

4 Watersheds Watershed Small watersheds combine into larger and end at sea Pollution in watershed reaches all other tributaries downstream Water used along watershed rivers decreases water available downstream Porosity Amount of space between particles in rock More porous rock holds more water Permeability Ability of a rock to allow water to flow through it Permeable Material that water can flow through (ex: gravel) Impermeable Material that water cannot flow through (ex: granite, clay) Having more space between individual rocks will make the ground more permeable Aquifer Underground formation containing groundwater Like a sponge Usually contain permeable materials May be confined between impermeable rock Aquifer Dry, Impermeable rock forms lower boundary The water table forms the upper boundary Recharge Zone Where surface water soaks into the ground Refills water in aquifer More permeable rock Quicker recharge of aquifer Sensitive to pollution Easily passes into aquifer 4

5 Well Hole dug or drilled for groundwater Usually deep into saturated zone Prevent drying up in drought Dry up if water table is below depth of well Water Use 9,087,000,000,000 m 3 /yr About 70 % is used on agriculture Amount/split varies based on nation s wealth Global Shortage of clean water 1/3 rd of people are affected Water Use Water Use Water Use Residential Water Use 8 % of total water use Varies widely throughout the world US 80 gal/day, India 11 gal/day 50 % used inside home Ex: cleaning, washing, etc. ~ 50 % used outside home Ex: watering lawn/washing cars Industrial Water Use 22 % of total water use 18 billion gal/day in US Manufacture goods, dispose of waste, generate power Most water used in industry cools power plants Water Use Agricultural Water Use 70 % of total water use 80 gallons of water to produce 1 ear of corn About 80% of water used for agriculture evaporates before being absorbed Irrigation Watering plants Usually uses overhead sprinklers Much of the water is wasted Drip-irrigation is becoming common Individual plants are watered Water Use 5

6 Moving water from source to where needed Used since ancient times Why? Bring water to make a dry area habitable Create reservoir Generate electric power Canal Man-made water channels Built to cross impossible boundaries or divert water to dry climates Ex: Panama Canal Aqueducts Bridges that divert water Often to arid climates or across valleys Common in ancient Rome Dam Any obstruction to block flow of water Often used to slow water movement or prevent droughts/floods Reservoir Artificial lake created by dam Frequently used to provide drinking water Dam Benefits Flood control Drinking water Irrigation Recreation Industry Electrical Energy Dam Costs Land behind dam can flood Nutrients blocked from reaching down river Displace people from homes Potential failure 6

7 Water Pollution Introduction of any chemical, physical, or biological agents into water that: Degrade water quality Adversely affect the organisms that depend on the water Water Pollution Water Pollution Point-Source Pollution Pollution from a single source Nonpoint-Source Pollution Pollution from several different sources Difficult to identify because they enter bodies of water many different ways 96% of all water pollution Pathogens Disease-causing organisms Mostly from nonpoint sources Human/animal waste Most human health effects Ex: bacteria, viruses, protozoa, and parasitic worms Nutrient Pollution Buildup of nitrogen and phsophorus Mostly nonpoint-sources Seen in healthy lakes to an extent Lower oxygen levels and block sunlight Create algae blooms and red tide Toxic Chemicals Mostly from nonpoint-sources Farms, lawns, Wastewater Organic Pesticides, fertilizers, detergents plastics, oil, VOC (volatile organic compounds) Inorganic Acids, salts, heavy metals Can affect ph levels Heavy Metals Cadmium: burning of fossil fuels, paint, batteries and electroplating Chromium: air-conditioning coolants, timber treating works, leather tanning works and electroplating Copper: vehicle brake pads, natural minerals, copper plumbing, irrigation water and pesticides Zinc: vehicle tires, motor oils, galvanizing works, corrosion from galvanized iron Lead: mainly car exhausts and engines Arsenic: brake linings, fluid leaks, vehicle emissions 7

8 Sediment Pollution Clouds up water to prevent photosynthesis Lowers water quality Result of runoff and erosion Causes: mining, clear-cutting, farming Thermal Pollution Temperature of a body of water rises Warmer water holds less oxygen Often due to power plants discharging water from their cooling systems Can also be due to tree removal Bioaccumulation Buildup of pollutants higher up the food chain Water pollution can effect an ecosystem immediately or slowly over time Water Pollution Ocean Pollution Ocean Pollution 85% of ocean pollution comes from activities on land Runoff In some areas ships are allowed to dump wastewater/garbage directly into the ocean Affects coastlines the most 5% of ocean pollution Each year: ~37 million gal from tanker accidents mil gal from nonpointsources on land Treatment Some oil will evaporate on its own Controlled burns Skimming from surface Dispersants Break oil into droplets 8

9 Exxon-Valdez March 24, 1989 Struck a reef off the coast of Alaska Largest spill in US at the time 10,000,000+ gallons Remote location hindered cleanup Exxon-Valdez 23,000 gallons are still in the soil near the wreck Killed 100,000+ seabirds, 12 otters, 22 orcas, 300 seals, 247 bald eagles Deepwater Horizon April 20, 2010 Methane bubble rose out and exploded, sinking platform 11 workers died in explosion Largest spill in history 210,000,000 gallons Deepwater Horizon Not capped until July 15, 2010 Flooded gulf coast with oil BP owed > $ 42 billion as a result Water Treatment Wastewater Water polluted from home or industrial use Must be cleaned before returned to a river or lake Water Treatment Process of cleaning water for drinking or industrial use Water Treatment Water Treatment Starts with filtering large solids Coagulants are added Cause solids to form clumps called floc Floc settles and is pumped out Second filtering by fine grain sand removes remaining solids 9

10 Water Treatment Wastewater Water Treatment Chlorine is added to kill pathogens and prevent future growth Aeration breaks down materials and drives out unwanted gases Chemicals may be added (Ex: Fluoride) and the water is pumped out to consumers Sewage Sludge Solid material that remains after water treatment Often contains toxic chemicals Disposed as hazardous waste Incinerated and ashes are buried If toxicity can be reduced, it can be used as fertilizer Can be combined with clay and made into bricks 10