Salt water systems

• 74% of the Earth's surface is covered by water
• Forms of water on Earth

  • Ice
  • Liquid water
  • Water vapor
• Potable water


  Water that humans can drink safely
• Potable water must be fresh and clean
• Only 0.003% of Earth's water is drinkable
• 97% of Earth's water is salt water
• Freshwater on Earth


  • 77% is locked up in ice
  • 22% is groundwater
  • 1% is in lakes, rivers and wetlands
• 0.0009% of all water on Earth is a gas in the atmosphere at any one time
• Water scarcity is a growing problem in some places
• Current technologies for harvesting fresh water from the air vary in cost and practicality
• Water quality


  How pure (clean) the water is
• Substances measured in water quality

  • Living organisms
  • Organic material
  • Minerals
  • Other chemicals
• Salinity


  The total amount of all salts dissolved in water
• Seawater has a higher salinity (~3.5%) than fresh water
• Hard water


  Has a high concentration of calcium and magnesium, leaves mineral deposits in appliances, makes it difficult for soap to lather
• Some organisms in freshwater can be harmful (Ex. E. coli)
• Water quality testing criteria

  • Taste
  • Odor
  • Turbidity
  • Color
  • Pollutants
  • Bacteria
  • Hardness
  • pH
  • Dissolved Oxygen
  • Solids, including dissolved solids
• Distillation


  Boiling water, water evaporates leaving salt behind, water vapor collected as pure water
• Reverse osmosis


  Forcing salt water through a membrane, water can pass but salt cannot
• Diversity


  The variety of species in an ecosystem
• A large diversity indicates a healthy environment
• The oceans contain many different environments, there is a greater diversity of organisms in saltwater than in freshwater
• Upper Zone


  1. From the shore down to where the plants stop growing

  2. Can find water lilies, bulrushes, small fish, insects, snails, worms
• Middle Zone


  1. Open water area that has light penetration

  2. Can find plankton, fish
• Lower Zone


  1. Deep water with no light penetration

  2. No plants

  3. Can find fish, bottom feeders
• Intertidal Zone


  • An area of shoreline that is not covered by water during low tide
  • Organisms here must survive pounding waves and times without water
• Estuary


  • Where the freshwater flows into saltwater, forming brackish water, a mix of fresh and salt water
  • Supports a large diversity of organisms
• Continental Shelf


  • The shallow area of the ocean that surrounds continents
  • The water here is warmer and light penetrates almost to the bottom
  • Rich in nutrients and supports a large diversity of organisms
• Oceanic Zone


  • The deep part of the ocean
  • Most of this zone receives no light and has little oxygen and nutrients
  • Supports a variety of small and large sized species
• Adaptation


  A physical characteristic or behavior of a species that increases its chance of surviving in its environment
• Environmental factors aquatic organisms must adapt to

  • Temperature
  • Light
  • Pressure
  • Salinity
  • Water movement
• Population


  A group of organisms of the same species that live in an area
• Population


  • The cod off Canada's east coast
• When ecosystems change, populations change
• In northern regions, populations of freshwater organisms change dramatically between seasons
• Populations swell in the summer and seem to disappear in the winter when the organisms hibernate or become dormant
• Changes can also be caused by breeding cycles
• Population change


  • Mosquito larvae live in a pond for a few weeks before becoming adults and flying away
• Short-term changes in populations


  Occur irregularly, don't last very long, can be caused by human activities or a natural event
• Short-term population change


  • A population of fish might decline temporarily after an oil spill