Material cycles

• Water cycle


  Continuous movement of water within the Earth and atmosphere, tying together major parts of the Earth’s climate system
• Water cycle processes


  1. Liquid water evaporates into water vapor

  2. Condenses to form clouds

  3. Precipitates back to earth as rain and snow

  4. Water in different phases moves through the atmosphere

  5. Liquid water flows across land

  6. Water flows into the ground

  7. Water moves through the ground

  8. Groundwater moves into plants

  9. Water evaporates from plants into the atmosphere

  10. Solid ice and snow can turn directly into gas

  11. Water vapor can become solid
• Evaporation

  Liquid water evaporates into water vapor and rises into the atmosphere
• Transpiration


  Plants release water vapor into the atmosphere through stomata
• Evapotranspiration


  Combines evaporation and transpiration, representing the overall loss of water from the earth’s surface
• Condensation


  Water vapor condenses into tiny water droplets or ice crystals forming clouds
• Precipitation


  Water droplets in clouds fall back to form rain and snow
• Runoff


  Liquid water flows across land
• Percolation


  Water flows deeper into the ground and reaches a saturated zone where it becomes underground aquifers
• Infiltration


  Water infiltrates the soil, moving through gaps and pores between soil particles and becoming groundwater
• Groundwater


  Water that infiltrates into the soil and becomes groundwater, moving through the subsurface completing the water cycle
• Plant uptake


  Groundwater moves into plants by absorbing water from the soil through their roots, transporting it through stems and leaves
• Sublimation

  Ice and snow transform directly into water vapor without melting into liquid water first
• Deposition


  Water vapor becomes solid
• Water influences climate variability and change

  Playing a key role in extreme events like drought and floods
• Human uses of water

  • Drinking
  • Industrial applications
  • Agriculture
  • Hydropower
  • Waste disposal
  • Recreation
• Water supplies are depleted

  Due to population growth, pollution, and development, worsened by climate variations and changes affecting the hydrologic cycle
• Climate change affects water availability

  Impacting economy, energy production, human health, transportation, agriculture, national security, natural ecosystems, and recreation
• Carbon cycle shows the movement of carbon in elemental and combined states on earth
• Diamond and graphite are the elemental forms of carbon
• In combined state, carbon is found as carbonates in minerals and as carbon dioxide gas in the atmosphere
• Carbon cycle is the process where carbon compounds are interchanged among the biosphere, geosphere, pedosphere, hydrosphere, and atmosphere of the earth
• Major steps involved in the carbon cycle include absorption of carbon in the atmosphere
• Forms of carbon

  • Elemental forms, combined state as carbonates in minerals, carbon dioxide gas in the atmosphere
• Carbon Cycle Steps


  1. Carbon in the atmosphere is absorbed by plants for photosynthesis

  2. Plants are consumed by animals and carbon gets bioaccumulated into their bodies

  3. Animals and plants die, decompose, and release carbon back into the atmosphere

  4. Some carbon becomes fossil fuels

  5. Fossil fuels are used for man-made activities, pumping more carbon back into the atmosphere
• Carbon Cycle on Land

  1. Carbon in the atmosphere is present as carbon dioxide

  2. Carbon enters the atmosphere through natural processes like respiration and burning fossil fuels

  3. Photosynthesis involves absorption of CO2 by plants to produce carbohydrates

  4. Carbon compounds pass along the food chain from producers to consumers

  5. Majority of carbon in the body is in the form of carbon dioxide through respiration

  6. Decomposers eat dead organisms and return carbon back into the atmosphere
• Oceanic Carbon Cycle

  1. Oceans act as a carbon sink, taking in more carbon than they release

  2. Marine animals convert carbon to calcium carbonate for hard shells

  3. When organisms with calcium carbonate shells die, their shells accumulate on the seafloor and eventually form limestone

  4. Limestone rocks weather and release carbon back into the atmosphere as carbon dioxide
• Carbon dioxide in the atmosphere plays a vital role in balancing energy and trapping long-wave radiations from the sun, acting like a blanket over the planet
• Disturbance in the carbon cycle can lead to serious consequences such as climatic changes and global warming
• Carbon is an integral component of every life form on earth, from proteins and lipids to DNA. All known life on earth is based on carbon
• The carbon cycle, along with the nitrogen cycle and oxygen cycle, plays a vital role in the existence of life on earth
• Biogeochemical cycle


  Cycle of essential nutrients in the biosphere
• Biosphere contains all the minerals, water, oxygen, carbon, and other essential nutrients to support life
• Biosphere is a closed system thus no chemicals can enter and leave this planet (Nutrients are recycled)
• Recycling


  The process of using and reusing materials
• Nutrient


  Compounds in foods essential to life and health, providing energy, building blocks for repair and growth, and substances necessary to regulate chemical processes
• Macronutrient

  Essential nutrients required in fairly large quantities such as carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulfur
• Micronutrient

  Essential nutrients utilized in small amounts such as iron, zinc, copper, and iodine
• Reservoir


  Represents the natural capital or nutrient pool from which the elements accumulated in large quantities on Earth
• Nitrogen


  The most abundant gas in the atmosphere (80% total volume of air in the atmosphere). Essential part of amino acids that make up proteins. Needed by living organisms to survive