Chapter 2

• Water


  The universal solvent carrying the dissolved gases, elements, substances, and organic compounds that form the basis of all plant and animal life on the planet
• Water cycle


  The basic unifying principle of everything referring to water on the planet
• Water cycle

  1. Evaporation

  2. Transport by wind

  3. Precipitation

  4. Drainage
• Water cycle


  • Model representing the interdependence and continuous movement of water in the solid, liquid and gas phases
• Hydrologic cycle


  Includes the components of evaporation, transport by wind, precipitation, and drainage
• Surface tension of water

  Enables a set of organisms - neuston or pleuston - to utilize the interface between the water and the atmosphere for support as well as for movement
• Dynamic viscosity


  The force required to move 1 kg a distance of 1 m in 1 second through a mass of water
• Components of the water cycle

  1. Precipitation

  2. Evaporation

  3. Transpiration

  4. Filtration

  5. Percolation

  6. Drainage
• Precipitation is water added to the Earth's surface from the atmosphere
• Evaporation is the transformation process of liquid water to gas (water vapor)
• Transpiration is the process by which plants release water vapor, which is dispersed into the atmosphere
• Filtration is the process by which water is absorbed by the soil
• Percolation is the process by which water moves through the soil and rock formations down to the phreatic level
• Drainage is the movement of displacement of the water on surfaces during precipitation
• Small comets


  Snowballs (called by scientists)
• According to Pielou (1998), the water cycle can be considered a life cycle, and the natural history of water on the planet is related to life cycles and the history of life
• The major rivers and lakes on Earth are important reserves of fresh water
• The velocity of the water cycle varies from one geological period to another, as well as the total proportions of fresh water and sea water
• World's major freshwater lakes

  • Superior: North America
  • Victoria: Africa
  • Huron: North America
  • Michigan: North America
  • Tanganyika: Africa: Ancient Lakes
  • Baikal: Asia: rich in diversity
  • Nyasa: Africa
  • Great Bear Lake: North America
  • Great Slave Lake: North America
  • Erie: North America
  • Winnipeg: North America
  • Ontario: North America
• In the southern part of South America, there are larger lakes, in surface area and volume, in Patagonia and the Andean Region
• The North American Great Lakes are important freshwater reserves and are an international water resource shared by Canada and the United States
• Groundwater


  Water found in the subsoil of the Earth's surface. It can be found in all regions around the world and is an important natural resource
• Important uses of groundwater

  • Domestic supply
  • Irrigation in rural areas
  • Industry
• The draining by rivers is the most important component of the water cycle
• The Amazon is the world's largest river
• Unsaturated zone


  Contains water and air
• Saturated zone


  Contains only water
• Recharge areas are a portion of the precipitation that reaches the Earth's surface and percolates down through the unsaturated zone to the saturated zone
• Important sources of groundwater deposits

  • Limestone
  • Dolomite
  • Basalt
  • Sandstone
• Brazil is estimated to contain between 12–16% of all the fresh water on the planet