EnviSci Chapter 8

• Biosphere

  • the sum of all living matter on the earth
  • interconnected with other three other spheres of the physical environment
• Three other spheres of the physical environment

  1. Lithosphere
  2. Hydrosphere
  3. Atmosphere
• Hydrosphere

  • includes all water at or near the earth's surface
• Atmosphere

  • envelope of gas that surrounds the earth
  • becomes progressively thinner with increasing altitude
• tectonic cycle - formation of new crust in some areas and its destruction in other
• plate tectonics - geological theory that proposes the lithosphere is composed of tectonic plates that are in constant motion relative to each other
• tectonic processes - formed new continents, mountain ranges, and moved existing continents across the surface of the earth
• hydrologic cycle - the continuous recycling of water between the oceans and the atmosphere
• evaporation - movement of water from the ocean or a lake to the atmosphere
• transpiration - contributes to atmospheric water content
• precipitation - movement of water from the atmosphere to the land or ocean
• Layers of atmosphere

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermosphere
  5. Exosphere
• Directly or indirectly disturb the biosphere

  1. Human technology
  2. Population growth
• Developed Countries

  1. United States
  2. Canada
  3. Japan
  4. Russia
  5. Australia
  6. New Zealand
  7. Europe
• Developing countries

  1. Africa
  2. South America
  3. India
  4. China
• Industrialization - driven by the energy consumption from coal, petroleum, and natural gas, otherwise known as fossil fuels
• Oil - the fuel most widely used
• Pollution - any environmental change that adversely affects the lives and health of living things
• factors affecting the atmosphere's ability to protect

  1. Agricultural Gases
  2. Industrial Gases
• Sources of carbon dioxide

  1. cellular respiration
  2. burning of wood or fossil fuel
• two main sinks of carbon dioxide

  1. plants
  2. oceans
• Greenhouse effect - it is thought to be responsible for the global warming; warming of the lower temperature caused by accumulation of certain greenhouse gases that allow rays from the sun to pass through, but then reflect or reradiate heat to the earth
• the average temperature of the earth has risen by 0.5 degrees Celsius over the past 100 years
• Climate Change - the change of the atmospheric condition for a long period of time. it can have biological as well as geopolitical and economic consequences
• Climate Fluctuations

  • occurs on both short term or long term time scales
  • have left evidences in the distribution of fossils, living forms, and their close relatives and locations of certain types of sedimentary rocks
• Paleoecology - branch of science that deals with such data in an attempt to reconstruct the environment of the distant past
• Methane - another atmospheric pollutant produced by oil and gas wells, rice paddles, etc.
• Greenhouse gases

  1. Carbon Dioxide
  2. Nitrous Oxide
  3. Methane
  4. Chlorofluorocarbons
  5. Halons
  6. Water Vapors
• Carbon Dioxide - product of burning fossil fuel or wood
• Nitrous Oxide - produced by fertilizers used and released from decomposition of animal wastes
• Methane - produced by bacteria, sediments, swamps, certain types of landfills, and in flooded rice paddles
• Chlorofluorocarbons - responsible to the depletion of the ozone layer in the upper atmosphere
• Halons - released from the fire extinguishers
• Water Vapor - considered as greenhouse gases
• Ozone

  • produced in the upper atmosphere when sunlight strikes oxygen atoms and causes them to temporarily combine
  • helps filter most of the high energy ultraviolet radiation that causes cancers and mutations
  • being destroyed by the release of gases containing chlorine atoms in the stratosphere
• Sulfur Oxide - formed when sulfur combines with atmospheric water vapor
• Smog - an urban problem caused by contribution of fuels
• Photochemical Smog - air pollutions that contains nitrogen oxides and hydrocarbons
• Carbon Monoxide - a gas that comes from burning of fossil fuels in the industrial regions
• Thermal Inversion - local occurrences of polluted air being trapped close to the surface