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What Factors Influence Earth’s Climate?
- Both climate and weather are driven by the sun
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Weather
- Weather: short-term fluctuations in a region over periods of hours or days
- temperature, humidity, cloud cover, wind, and precipitation
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climate
- Climate : long-term patterns of weather that prevail over years or centuries in a particular region
- The amount of sunlight and water and the range of temperatures determine the climate of a region
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Solar energy
- Solar energy drives the wind, ocean currents, and the global water cycle Short, high-energy ultraviolet (UV) rays
- Visible light
- Infrared wavelengths that we experience as heat
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The ozone layer
- The ozone layer, found in the middle atmosphere or stratosphere, is rich in ozone (O3) and absorbs much of the sun’s UV radiation
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Earth’s physical features also influence climate
- Earth’s curvature and its tilted axis as it orbits the sun cause uneven heating of the surface and seasonal changes in the directness of sunlight north and south of the equator
- Uneven heating, in conjunction with Earth’s rotation, generates air and ocean currents, which in turn are modified by land masses
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what Produces Seasons and Climate
Earth’s Curvature and Tilt
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Air Currents and Climatic Regions
 - The sun heats the Earth’s surface; the heat radiated from Earth warms the air
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- Warm air rises, cooling as it ascends; the water vapor in the air condenses and falls as rain
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Continents and mountains complicate weather and climate
- If Earth’s surface were uniform, climate zones would occur in bands corresponding to latitude
- However, the presence of irregularly shaped continents, which heat and cool more quickly than surrounding oceans, alters the flow of wind and water
- These factors result in the irregular distribution of ecosystems
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biomes based on altitude
- tropical forest
- tropical and scrub forest
- deciduous forest
- coniferous forest
- tundra
- ice and snow
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Mountains Create Rain Shadows
- water vapor is carried from the ocean by the prevailing winds
- Water falls as rain or snow as the air rises and cools
- Cool dry air sinks, warms, and absorbes water from the land
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There are four fundamental requirements for life
- Nutrients from which to construct living tissue
- Energy to power metabolic activities
- Liquid water to serve as medium in which metabolic activities occur
- Appropriate temperatures at which to carry out these processes- enzymes get denatured unless at a perfect temperature
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Terrestrial biomes
- Terrestrial biomes support characteristic plant communities
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Because plants cannot escape their conditions, they are precisely adapted to the climate of a particular region - Large land areas with similar environmental conditions and characteristic plant communities are called biomes
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Biomes are generally named after
- Biomes are generally named after the dominant type of vegetation
- Rainfall and temperature determine the soil moisture available to the plants
- the way that rainfall and temperature vary seasonally determines which plants can grow in a given region
- In groups
- Identify the different terrestrial biomes
- Biotic, abiotic characteristics
- Human impact
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Human impact on rain forests
- Agriculture can degrade soils quickly
- Nutrients are eroded away by heavy rains
- Exposed soils bake and become impenetrable
- Rain forests cut for lumber and burned for ranching and farming
- Researchers estimate that 25% of the carbon released into the atmosphere comes from cutting and burning tropical rain forests, exacerbating global warming
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Destruction of rain forests
- •Destruction of rain forests = 10 times the area of Connecticut , every year.
- •Over 50% of the world’s rain forests are already gone
- •a great deal of the Earth’s remaining biodiversity occurs in this biome
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all typpes of biomes
- Tropical deciduous forests
- The savanna
- Deserts
- Chaparral
- Grasslands
- Temperate deciduous forests
- Taiga
- Tundra
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Human impacts on freshwater lakes
- Nutrients carried into lakes from farms, feedlots, sewage, and suburban lawns accelerate eutrophication
- Lake Erie once suffered severe eutrophication (algea bloom)from phosphate-based detergents and farm runoff
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Human impact on rivers
- Rivers have been channelized (straightened and deepened) to facilitate boat traffic, to prevent flooding, and to allow farming
- This has increased erosion, because water flows more rapidly in channelized rivers
- In the U.S., northwestern and northeastern salmon populations have been severely reduced by hydroelectric dams, water diversion for agriculture, erosion from logging activities, and overfishing
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Wetlands
- Freshwater wetlands are called marshes, swamps, or bogs
- Wetlands are regions where soil is covered or saturated with water
- Many aquatic and some terrestrial plant species thrive in wetlands, which support dense growths of algae and phytoplankton, as well as both floating and rooted plants
- Wetlands act as giant sponges, absorbing water and then gradually releasing it into rivers or aquifers, which action safeguards against flooding and erosion
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Wetlands also serve as giant water filters and purifiers
- As water flows through them, suspended particles fall to the bottom
- Wetland plants and phytoplankton absorb nutrients such as nitrates and phosphates that have washed from the land
- Toxic substances, such as pesticides and heavy metals, may also be absorbed by wetland plants
- Soil-dwelling bacteria break down some pesticides, rendering them harmless
- Wetlands provide breeding grounds, food, and shelter for a great variety of birds, mammals, freshwater fish, and invertebrates, such as crayfish and dragonflies
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Human impact on wetlands
- The extent of wetlands in the U.S. has decreased by about half as a result of being drained and filled for agriculture, housing, and commercial uses
- Destruction of wetlands makes the water more susceptible to pollutants, reduces wildlife habitat, and may increase the severity of floods
- As a result of recent laws to protect wetlands, the rate of wetland loss in the U.S. has declined
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Coral reefs
- Coral reefs are complex formations that have accumulated over thousands of years from the calcium carbonate skeletons of corals
- The coral skeleton provides anchorage, shelter, and food for an extremely diverse community of algae, fish, and invertebrates
- Coral reefs might be considered the “ocean’s rain forests” since they are home to more than 90,000 known species, with many more yet to be identified
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Human impacts on coral reefs
- Anything that diminishes the water’s clarity harms the coral’s photosynthetic protists and hinders coral growth
- Runoff from farming, agriculture, logging, and construction carries silt and nutrients that promote eutrophication, reducing sunlight and oxygen
- Coral bleaching occurs when waters become too warm, causing the coral to expel the protists
- Inhabitants of coral reefs, along with the corals themselves, are being harvested by humans faster than they can reproduce
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Human impacts on the open ocean
- Two major threats to the open ocean are pollution and overfishing
- deliberate dumping by oceangoing vessels, oil spills, and agricultural runoff
- Overfishing, resulting from growing human populations
- International efforts are now being made to prevent overfishing by establishing fish quotas and creating marine reserves
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Hydrothermal Vent Communities
snail, worms tolerate temperatures up to 248 degrees
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