Chapter 58: The Biosphere - Effects of Sun, Wind, Water o Biosphere: includes all living communities on earth o Influences of global patterns of life  Solar radiation reaching different areas  Global atmospheric circulation influences oceanic circulation  Some parts of earth’s surface receive more energy from the sun than others  Angle of incidence: how the Sun’s rays strike the spherical Earth  Earth’s rotations affect climate - Seasons  Global circulation patterns - Heating at equator causes air to rise from surface to atmosphere - Radiation at the equator provides heat for water evaporation - Warm air moves north and south - cooler air flows towards equator - air descends at 30 degrees latitude (desert regions)- 60 degrees air rises again o The Coriolis Effect: curvature of the paths of the wind due to Earth’s rotation  Northern hemisphere: winds curve to the right  Southern hemisphere: winds curve to the left; blow westward and towards the equator  Ocean currents are largely driven by winds o Regional and local differences affecting ecosystems  Rain shadows- Rain falls as air rises and land remains dry on the leeward side of the mountain Monsoons: seasonally shifting winds - Asia’s size causes heating and cooling of surface causes massive regional shifts in wind patternso Winds blow water interior in summer o Winds blow to water in the winter o Winds affect duration and strength of rainfall patters Conditions such as temperature change with elevation - Temp falls about 6 degree Celsius for every 1000 m increase in elevationo Microclimates: highly localized sets of climatic conditions  Gaps in forest canopy have high air temperature and low humidity  under a log in a forest has low air temperature and high humidity - Biomes o Biome: a major type of ecosystem on land o Biomes are each defined by sets of regional climatic conditions and are named for their vegetal structures o Tropical Rain Forests  140-459 cm rain/year  Richest ecosystems on land  High temperature, rainfall, and diversity  Ex: Amazon rain forest o Savanna  50-125 cm rain/year  tropical or subtropical grasslands  transitional ecosystem between rainforests and deserts  ex: Serengeti o Deserts  25-40 cm rainfall/year plants and animals can’t depend on any rainfall 30 degrees N and S latitudes due to global air circulation patterns sparse vegetation, animals adapted to little water  ex: Sahara o Temperate Grasslands or Prairies  Rich soils Grasses with deep roots  Converted to agricultural roots in NA  Adapted to periodic fire  Ex: Great Plains o Temperature Deciduous Forests  Mild but seasonal climates and plentiful rains o Temperature Evergreen Forests  Occur along coastlines with temperate climates o Taiga and Tundra  Both stretch in unbroken circles around the entire globe o Freshwater Habitats  2% of Earth’s surface  Life depends on oxygen availability from photosynthesis and aeration from atmosphere- Removed by animal and detritivore respiration- Warm water has less O2 than cool water  Lake and pond habitats change with depth- Intensity of light decreases with depth - Photic: light penetrates and photosynthesis is possible - Littoral zone: shallows at edge of lake- Aphotic (benthic): below light penetration  Thermal stratification: warm water is less dense than cold water and tends to float on top- Thermocline: a transition layer between warm and cold waters - Cuts of oxygen supply to bottom layer - Anoxia: oxygen depleted waters - Wind can mix and overturn layers  Oligotrophic water: low in nutrients, usually high in oxygen - Crystal clear because of low organic matter- Light penetrates deep  Eutrophic water: high in nutrients, densely populated with algae and plant material- Low in dissolve O2 in summer- Light doesn’t penetrate water column o Marine Habitats  71% earth’s surface is ocean  continental shelves: near coastline, water is not very deep  principle primary producers are phytoplankton  average depth of open ocean is 4000-5000 m  Ocean Zones - Open oceans have low primary productivity - Oligotrophic ocean  low nutrient levels; biological deserts - continental shelf ecosystems provide abundant resources - neritic waters: waters over shelves with high concentrations of nitrates and other nutrients; shallow upwelling occurs o 99% open ocean food comes from neritic watero petroleum comes from shelves Estuaries: shelf ecosystems where fresh water from streams or rivers mix with ocean water -Intertidal habitat: area exposed to air at low tide but under water high tide -Salt marshes: in intertidal zones-Mangrove swamps: occur in tropical and subtropical intertidal zones Banks: local shallow areas on shelves; fishing Coral reefs occur in subtropical and tropical latitudes with stony corals -Algal symbioses: cnidarians and dinoflagellates Upwelling regions: localized places where deep water is drawn consistently to the surface El Nino Southern Oscillation (ENSO)-2-7 years on an irregular and unpredictable basis -coastline waters are profoundly warm-primary productivity low -weakening of east to west trade winds -upwelling only recirculates the thick, warm surface layer -wreaks havoc on ecosystems o plankton abundance drops, fish stocks disappear, sea birds and sea lions crash -heavy rains produce abundant seeds, land birds flourish, rodent and predator populations growDeep Sea: cold dark place with fascinating communities and no season -Food originates from photosynthesis in sunlit water-99% eaten as it drifts down -animals are small bodied and thinly distributed-hydrothermal vent communities: lots of life o large bodied animalso depend on sulfur oxidizing bacteria for primary production instead of the sun o water temp can be up to 350 degrees Celsius -Human Impacts: Pollution o DDT: insecticide sprayed in US after WWII that caused population of large birds to plummet because of biomagnification Egg shells became thin and broke during incubation o Freshwater habitats threatened by pollution and resource use o point source pollution: comes from an identifiable location ex: factories and sewage treatment plants laws and technologies can be applied because the source is known o diffuse pollution: ex: eutrophication caused by excessive runoff of nitrates and phosphatesdissolved O2 declines; fish species change; carp take