water and carbon cycle

• Earth is the only planet where water in its liquid form exists. In other planets, water occurs in the form of ice or vapor.
• As seen from space, Earth looks mostly blue and white because of water, snow, ice, and clouds on its surface.
• Hydrosphere


  The part of the Earth's subsystem containing the oceans, lakes, streams, underground water, and snow and ice
• The hydrosphere makes up about 71% of the Earth's surface.
• Places where water exists

  • Atmosphere
  • Geosphere
  • Biosphere
• Hydrologic cycle


  The movement of water around the Earth's surface and its subsystems
• Hydrologic cycle


  • Consists of interconnected pathways and reservoirs
  • Maintains the total amount of water globally, despite local fluctuations
• Hydrologic cycle


  1. Evaporation

  2. Transpiration

  3. Sublimation

  4. Condensation

  5. Precipitation
• Heat from the sun provides energy for the movement of water in the hydrologic cycle.
• About 80% of water vapor in the atmosphere evaporates from the ocean.
• Transpiration contributes to about 10% of the water vapor in the atmosphere.
• In high altitudes, ice can directly transform into water vapor through sublimation.
• As air rises and cools, water vapor condenses to form water droplets and clouds.
• When water droplets or ice crystals in clouds become large and heavy, precipitation occurs.
• Condensation


  The process by which water vapor in the air is converted into liquid water
• Evaporation


  The process by which liquid water is converted into water vapor
• Evapotranspiration


  The process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants
• Ocean


  A large body of salt water that covers a considerable part of the globe
• Clouds


  Visible masses of condensed water vapor floating in the atmosphere, typically high above the ground
• Water vapor


  Water in the form of an invisible gas
• Ice


  Water in the solid state
• Snow


  Precipitation in the form of small white ice crystals
• Precipitation


  Water that falls to the ground in the form of rain, snow, sleet, or hail
• Stream flow


  The flow of water in a natural stream or river
• Surface runoff


  Water that flows over the land surface and into bodies of water, rather than infiltrating the ground
• Infiltration


  The process by which water on the surface enters the soil
• Percolation


  The movement of water through the pores and spaces in soil or rock
• Groundwater discharge


  The flow of groundwater into streams, lakes, or the ocean
• Infiltration


  Rain that falls into the land surface penetrates the soil
• Surface runoff


  When the soil becomes saturated, rainwater may flow over land and will join other bodies of water such as streams, lakes, and oceans
• Groundwater storage


  Part of the water that infiltrates the ground will be stored as groundwater
• Evaporation and transpiration


  Some of the water that infiltrates the ground will be absorbed by plants or will directly evaporate
• Snowmelt


  Snow usually remains on the ground for one or more seasons and eventually melts and contributes to the water in streams
• Glacier melt


  Water is locked up as ice in glaciers for a long time. Given the right conditions, the glaciers will eventually melt, evaporate, and return to the oceans
• Water as ice


  • Floats on water in liquid state
  • Expands when it freezes, forming ice
  • Expansion of ice allows it to occupy more volume per unit weight, making its density less than that of water
  • This property of water is essential in sustaining life
  • Protects aquatic ecosystems during the winter because the frozen water or ice on top insulates the bottom water
• Ocean


  A vast body of saline water
• Oceans


  • Atlantic Ocean
  • Pacific Ocean
  • Indian Ocean
  • Arctic Ocean
  • Southern Ocean
• The total volume of water in the world's oceans is about 1340 million sq. km
• Salinity


  The saltiness of saltwater
• Major chemical elements present in seawater

  • Sodium ions
  • Chlorine ions