The Earth contains several biomes, each with temperature ranges, presence and depth of water, freshness or brackishness of water, annual rainfall, presence or absence of sunlight, flora and fauna which thrive in specific environments. Biomes can be classified in terms of their landed and aquatic nature, or in broad categories by ranges of latitude and relation to the poles and the equator. In a comprehensive categorization of biomes, the following is a basic introduction with links to two sites that offer comprehensive information.
There are generally eight biomes of the Earth’s surface:
The Arctic and Antarctic biomes.
Desert . Deserts cover about 20 percent of the Earth’s surface, with the majoritiy of land mass lying between the Tropic of Cancer and the Tropic of Capricorn. But there are major deserts that lie outside of these latitudes. Deserts are classified as having little or no rainfall, extremes of temperatures that are usually very hot in the day and very cold at night. The Gobi and the Antarctic deserts are constantly very cold. The only semi-arid desert is the Great Basin of the United States.
Tundra: Arctic and Alpine are generally cool or cold and dry.
Tiaga, Boreal or Coniferous Forest: These are the largest land biomes on Earth, covering 17% of the land mass. There are generally in North America, Northern Europe and Northern Asia.
Decidious Forest, or Temperate Deciduous Forest and Temperate Boreal Forest. Temperate means that temperatures maintain a warm average temperature 75 F to 86F, or 24C to 30C. However temperatures can range from very warm to very cool, depending on altitude. Rainfall and snow combined average about 2-5 feet or 0.5 to 1.5 meters. Humidity is generally high with a range of 60% to 80%.
Grasslands of Tropical Savannah, Prairie, Pampas, or Chaparral: Can be coastal, cool and rainy or with very hot seasons. Can be in very windy locations inland.
Rainforest, Tropical or Temperate: Rainfall that ranges from massive annual amounts to seasonal, adequate rainfall. Temperatures can range from warm to very cold, with seasonal variations in the Temperate Rainforests. The general division places the Tropical Rainforests in a band that lies between the Tropic of Cancer and the Tropic of Capricorn, with the Temperate Rainforests outside of the tropics, and mostly in the northern latitudes. Tropical rainforests have warm to very warm average temperatures and large rainfalls. Temperate rainforests have cool to very cool climates and seasonal rainfall and snow.
Other biomes include:
Freshwater Marsh: Near creeks, streams, lakes or rivers.
Wetlands: Have many names and types, including bogs, fens, sloughs, moors, and marshes. Wetlands can be in cool or warm zones.
Swamp: These are warm areas that range from wet to very wet.
The Ocean and its Intertidal, Coral Reef, Sunit (Euphotic), and Twilight (Disphotic) zones
Biomes can be classified by how wet or dry they are. Some have massive annual rainfall, others have little or no rainfall, and others have seasonal rainfall. Driest: Desert and the Tundra. Dry or wet depending on the season: Chaparral or Grassland Adequate wetness: Temperate and Deciduous Forests Very Wet: Tropical Rainforest and Swamp
Surface Biomes can be classified by temperature, whether they are always very cold, have wide ranges of seasonal temperature, or are always very warm or hot. Coldest: Arctic Tundra. Cool year round: Coniferous Forest and Cave. Both cool and warm seasons: Chaparral and Temperate Deciduous Forest . Hot and cool, with some cold seasons: Savannah. Warm or always warm: Swamps and Tropical Rainforests.
Other climate related issues with biomes can include monsoonal activity, extremes of drought and flood, extremes of heat and cold, altitude, and location within the Earth’s crust or in the depths of the Earth’s oceans and lakes.
For an excellent introduction to the Earth’s biomes, go to Enchanted Learning or BluePlanet. Each site has maps and detailed facts about the biomes as well as the fauna and flora of the biomes.