Ch. 4 Global Climates and Biomes

Global processes determine weather and climate
1. climate: The average weather that occurs in a given region over a long period of time.
  1. Regional differences in temperature and precipitation
    1. unequal heating of Earth by the Sun, atmospheric convection currents, the rotation of Earth, Earth’s orbit around the Sun on a tilted axis, and ocean currents.
2. Earth's Atmosphere
  1. troposphere: A layer of the atmosphere closest to the surface of Earth, extending up to approximately 16 km (10 miles) and containing most of the atmosphere’s nitrogen, oxygen, and water vapor.
  2. stratosphere: The layer of the atmosphere above the troposphere, extending roughly 16 to 50 km (10–31 miles) above the surface of Earth.
    1. Beyond the stratosphere are the mesosphere, the thermosphere, and farthest from Earth, the exosphere
      1. thermosphere is also interesting because it contains charged gas molecules that, when hit by solar energy, begin to glow and produce light
        northern lights, or aurora borealis & southern lights, or aurora australis
3. Unequal heating of Earth
  1. albedo: The percentage of incoming sunlight reflected from a surface.
4. PROPERTIES OF AIR Air has four properties that determine how it circulates in the atmosphere: density, water vapor capacity, adiabatic heating or cooling, and latent heat release.
  1. saturation point: The maximum amount of water vapor in the air at a given temperature.
  2. adiabatic cooling: The cooling effect of reduced pressure on air as it rises higher in the atmosphere and expands.
  3. adiabatic heating: The heating effect of increased pressure on air as it sinks toward the surface of Earth and decreases in volume.
    1. latent heat release: The release of energy when water vapor in the atmosphere condenses into liquid water.
      1. FORMATION OF CONVECTION CURRENTS
        Hadley cell: A convection current in the atmosphere that cycles between the equator and 30° N and 30° S.
        intertropical convergence zone (ITCZ): An area of Earth that receives the most intense sunlight; where the ascending branches of the two Hadley cells converge.
        polar cell: A convection cell in the atmosphere, formed by air that rises at 60° N and 60° S and sinks at the poles, 90° N and 90° S.
        GYRES Global prevailing wind patterns play a major role in determining the direction in which ocean surface water moves away from the equator
        UPWELLING Ocean currents also help explain why some regions of the ocean support highly productive ecosystems.
        THERMOHALINE CIRCULATION Another oceanic circulation pattern, thermohaline circulation, drives the mixing of surface water and deep water. Scientists believe this process is crucial for moving heat and nutrients around the globe.
        HEAT TRANSPORT Ocean currents can affect the temperature of nearby landmasses.
        El NiÑo–Southern Oscillation (ENSO): The periodic changes in winds and ocean currents, causing cooler and wetter conditions in the southeastern United States and unusually dry weather in southern Africa and Southeast Asia.
        rain shadow: A region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean causing precipitation on the windward side.
Aquatic biomes are categorized by salinity, depth and water flow
1. Aquatic biomes fall into two broad categories: freshwater and marine. Freshwater biomes include streams, rivers, lakes, and wetlands. Saltwater biomes, also known as marine biomes, include shallow marine areas such as estuaries and coral reefs as well as the open ocean.
  1. photic zone: The upper layer of water in the ocean that receives enough sunlight for photosynthesis.
    1. aphotic zone: The layer of ocean water that lacks sufficient sunlight for photosynthesis.
      1. chemosynthesis: A process used by some bacteria in the ocean to generate energy with methane and hydrogen sulfide.
2. Streams and Rivers are characterized by flowing fresh water that may originate from underground springs or as runoff from rain or melting snow. Streams (also called creeks) are typically narrow and carry relatively small amounts of water. Rivers are typically wider and carry larger amounts of water.
3. Lakes and Ponds
  1. littoral zone: The shallow zone of soil and water in lakes and ponds where most algae and emergent plants grow.
  2. limnetic zone: A zone of open water in lakes and ponds.
  3. phytoplankton: Floating algae.
  4. profundal zone: A region of water where sunlight does not reach, below the limnetic zone in very deep lakes.
  5. benthic zone: The muddy bottom of a lake, pond, or ocean.
4. freshwater wetland: An aquatic biome that is submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation.
5. salt marsh: A marsh containing nonwoody emergent vegetation, found along the coast in temperate climates.
6. mangrove swamp: A swamp that occurs along tropical and subtropical coasts, and contains salt-tolerant trees with roots submerged in water.
  1. intertidal zone: The narrow band of coastline between the levels of high tide and low tide.
    1. coral reef: The most diverse marine biome on Earth, found in warm, shallow waters beyond the shoreline.
      1. coral bleaching: A phenomenon in which algae inside corals die, causing the corals to turn white.
Variations in climate determine the dominate plant growth forms of terrestrial forms
1. biome: A geographic region categorized by a particular combination of average annual temperature, annual precipitation, and distinctive plant growth forms on land, and a particular combination of salinity, depth, and water flow in water.
  1. tundra: A cold and treeless biome with low-growing vegetation.
    1. permafrost: An impermeable, permanently frozen layer of soil.
    2. small woody shrubs, mosses, heaths, and lichens, can grow in shallow, waterlogged soil and can survive short growing seasons and bitterly cold winters
  2. boreal forest: A forest made up primarily of coniferous evergreen trees that can tolerate cold winters and short growing seasons.
    1. (sometimes called taiga) are forests made up primarily of coniferous (cone-bearing) evergreen trees that can tolerate cold winters and short growing seasons
      1. poorly suited for agriculture. However, these forests serve as an important source of trees for pulp, paper, and building materials. As a result, many have been extensively logged.
  3. temperate rainforest: A coastal biome typified by moderate temperatures and high precipitation.
    1. combination of mild temperatures and high precipitation supports the growth of very large trees
    2. temperate seasonal forest: A biome with warmer summers and colder winters than temperate rainforests and dominated by deciduous trees.
  4. woodland/shrubland: A biome characterized by hot, dry summers and mild, rainy winters.
  5. temperate grassland/cold desert: A biome characterized by cold, harsh winters, and hot, dry summers.
  6. tropical rainforest: A warm and wet biome found between 20? N and 20° S of the equator, with little seasonal temperature variation and high precipitation.
    1. tropical seasonal forest/savanna: A biome marked by warm temperatures and distinct wet and dry seasons.
  7. subtropical desert: A biome prevailing at approximately 30? N and 30° S, with hot temperatures, extremely dry conditions, and sparse vegetation.
    1. hot deserts, includes the Mojave Desert, Sahara Desert, Arabian Desert, Great Victoria
Earth is characterized by patterns of temperature and precipitation. These patterns arise from the circulation of air and ocean water, which is ultimately driven by unequal heating of Earth by the Sun, the rotation of Earth, and Earth’s geographic features. Geographic variations in temperature and precipitation have led to the development of distinct terrestrial biomes, which are defined by their unique plant communities, and distinct aquatic biomes, which are defined by their particular physical conditions.

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Ch. 4 Global Climates and Biomes

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	Created by Leilani Wojtal about 9 years ago