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Water

Water. Chapter 5. Our water resources. Life on Earth would be impossible without water Living organisms contain more water than any other substance Renewable resource that is continuously circulated by the water cycle. The Water Planet. 70 % of Earth’s surface is water

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Water

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  1. Water Chapter 5

  2. Our water resources • Life on Earth would be impossible without water • Living organisms contain more water than any other substance • Renewable resource that is continuously circulated by the water cycle

  3. The Water Planet • 70 % of Earth’s surface is water • 97% of that is salt water • That means on 3% of all water on Earth is fresh water • Most is frozen in the icecaps

  4. Fresh Water Resources • A. Surface water- water above ground: lakes, pond, rivers and streams • Watershed- entire area of land that is drained by a river

  5. Fresh Water Resources • B. Rivers of Controversy • 1. Why are there conflicts over water rights? Many • people rely on river water as a water supply. • 2. Dams • -A dam is a structure built across a river it restricts the flow of water downstream • water collects behind the dam and a reservoir forms

  6. Dams • What are some advantages to damming rivers? • -in a drought there is still water source • -flood control • -source of electricity • What are some disadvantages to damming rivers? • -ecosystems destroyed • -expensive • -restricts water flow down stream

  7. Fresh Water Resources • C. Ground water • 1. Ground water is water that soaks into the ground • 2. Aquifers are...porous rock formations that hold groundwater

  8. Solutions to water shortages • 1. Desalinization • process of removing salt from sea water • Disadvantages to desalinization • EXPENSIVE • Methods of desalinization • 1) Distillation • heat is used to evaporate water from salt • as water evaporates the salt is left behind • 2) Reverse osmosis • pressure is used to push water thru a semi • permeable membrane that will not allow salt to pass

  9. Solutions to water shortages • 2. Towing water • Moving it from one place to another • Icebergs • PROBLEMS • -Icebergs are hard to tow • -they melt • -hard to transport on land

  10. Solutions to water shortages • 3. Water Conservation: • Take shorter showers • Install water saving devices: faucets, toilets, shower heads etc.

  11. Freshwater Pollution • Water pollution is when chemical, physical or biological agents get into water and it degraded the water quality and affects organisms that depend on it

  12. Kinds of Pollutants • 1. Pathogens • disease causing organisms in water • comes from human waste or untreated sewage or animal waste • 2. Organic Matter • biodegradable remains of animals and plants –include feces • these come from non point sources • 3. Organic Chemicals • pesticides, fertilizers, plastics, detergents, gas, oil and other materials made from fossil fuels • these come from non point sources • 4. Inorganic Chemicals • acids, salts, toxic metals • from point and non point sources

  13. Kinds of Pollutants (continued) • 5. Toxic Chemicals • metals like lead, mercury and cadmium • come from household chemicals or industry • 6. Physical Agents • heat or solids • 7. Radioactive Waste • waste from a nuclear power plant

  14. Types of Water Pollution • 1. Point Pollution • pollution discharged from a single source • Examples – factory or treatment plant • 2. Non-point Pollution • pollution that comes from many sources • Examples - runoff

  15. Water pollution and ecosystems • Bioaccumulation – AKA: biological magnification • it is an increase of toxics at the top of the food chain • examples: DDT and Eagles, mercury in fish • Thermal Pollution • caused when excess heat gets released into the water • Excess heat can cause fish kills because warm water hold less dissolved oxygen than cooler water so fish suffocate

  16. Water pollution and ecosystems • Eutrophication • Containing excess nutrients • Occurs from decompositions- adds nutrients to the water -plants take root and sedimentation starts • Artificial eutrophication • fertilizers or other inorganic plant nutrients get into water • the fertilizer causes water plants to grow in excess (pond scum)

  17. Cleaning up Water Pollution • 1. 1972: Clean Water Act • goal to make surface waters fit for fishing and swimming • banned pollution discharge into water • required that metals be removed from waste water • 2. 1972: Marine Protection, Research & Sanctuaries Act • gave the EPA power to control the dumping of • sewage and toxins into the ocean • 3. 1975: Safe Water Drinking Act • protects both groundwater and surface water from pollution • 4. 1980: CERCLA – superfund • makes owners, operators, and customers who use • hazardous waste responsible for their clean up

  18. Ocean Pollution • 85% of pollution in the ocean comes from activities on land – runoff or dumped • Oil spills also...contaminate ocean water • Plastic is also an ocean pollutant because...it is not biodegradable • animals eat the plastic or get tangled in it

  19. Preventing Ocean Pollution • 1) MARPOL- prevents pollution from Oil tankers • prevents plastics and oils from being discharged into the oceans • 2) Oil pollution Act of 1990 requires that all oil tankers have double hauls

  20. Who owns the oceans? • If we don’t know who owns them…who should clean them up? • The Law of the Sea Treaty: • Territorial sea 12 nautical miles from nations coastline • Exclusive economic zone: 200 nautical miles from coastline • Signed by 134 countries USA was NOT one of them

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