XVIII' Environmental Science

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XVIII. Environmental Science

• A. Definition
• B. Biodiversity
• C. Biomes
• D. Climate
• E. Lakes
• F. Environmental Issues

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A. Definition

• 1. Branch of science concerned with environmental
  issues
• 2. Biotic environment- communities, populations,
  individuals
• 3. Abiotic environment- rocks, minerals,
  chemicals

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B. Biodiversity

• 1. Alternatively, species density or biological
  richness
• 2. Total number of species in an ecosystem the
  resulting complexity of interactions among them
• 3. of species pos. prop. to energy input
• 4. Large energy input results in high 1o
  production which results in more niches
• 5. High- tropical rain forest coral reefs low-
  deserts tundra

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C. Biomes

• 1. Large geographical area with similar
  environmental (climate) conditions
  characteristic communities
• 2. Tropical rain forest, savanna, desert,
  temperate grassland, temperate deciduous forest,
  temperate evergreen forest, taiga, tundra,
  (ocean biomes)
• 3. Biomes composed of ecosystems
• 4. Biosphere- all biomes, Earth

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D. Climate

• 1. A common pattern of weather, temperature,
  precipitation, wind
• 2. Latitude determines solar heat annual
  seasons
• 3. Microclimate- variation within an ecosystem
• 4. Elevation
• 5. Rain Shadows

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4. Elevation

• a. Air temperature decreases about 6oC for every
  1000m increase in elevation
• b. Changes in elelvation affect climate in same
  way as changes in latitude

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5. Rain Shadows

• a. Humid winds from ocean blocked by mountain
  ranges
• b. Humid ocean air rises cools causing
  precipitation on windward mountain side
• c. Cool dry air descends on leeward side
  resulting in arid or desert regions

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E. Lakes

• 1. Lake ecosystems studied separately but are
  strongly connected to terrestrial surroundings
• 2. Wetlands, rivers, springs contribute
  inorganic organic inputs
• 3. Zones
• 4. Thermal Stratification
• 5. Nutrient Levels

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3. Zones

• a. Littoral- shallow area near shore plants,
  algae herbivores
• b. Limnetic- middle surface water, zooplankton
  fish
• c. Profundal- deepest areas, no light, fish
  decomposers
• d. Lentic- still waters lakes, ponds, swamps
• e. Lotic- moving waters streams rivers

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4. Thermal Stratification

• a. Occurs in temperate lakes
• b. Temperature differences result in density
  layers
• c. Epilimnion- warmer water above thermocline
• d. Hypolimnion- colder water below thermocline
• e. Winds fall/spring temperature changes cause
  turn overs

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5. Nutrient Levels

• a. Oligotrophic lake- nutrient poor lake, little
  biodiversity
• b. Eutrophic lake- over loaded with nutrients,
  Phosphorus Nitrogen
• c. Point sources- dysfunctional sewage plants
• d. Nonpoint sources- runoff carries fertilizer
  organic matter
• e. Eutrophication Process

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a. Oligotrophic lake
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b. Eutrophic lake-
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e. Eutrophication Process

• 1.) Excess nutrients (P N) cause algal blooms
• 2.) Algal growth exceeds carrying capacity, algae
  die sink
• 3.) Profundal decomposers (bacteria) breakdown
  algae use large amounts of dissolved oxygen
  (D.O.)
• 4.) D.O. levels decrease kill fish

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F. Major Environmental Issues

• 1. Fossil (organic) fuels Global
  Warming/Climate Change
• 2. Pollution
• 3. Acid Precipitation
• 4. Invasive Species

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1. Global Warming/Climate Change

• a. 50-80 correlation between greenhouse gases
  increased temperature, lt1oC since 1890
• b. Greenhouse gases, CO2 (organic fuels), CH4
  (rice cattle) NOX (auto fuels)
• c. Greenhouse gases build up in atmosphere
  prevent heat from radiating back into space
• d. Increase temperature may be result of solar
  activity increased temp. on Mars
• e. Increased greenhouse gases may result in lower
  temperatures

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2. Pollution

• a. Air, soil, water
• b. Most biologically harmful pollutants are
  hydrophobic
• c. Not metabolized sequestered into biomass of
  organisms
• d. Bioaccumulation- magnification of pollutants
  as they progress up the food chain

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3. Acid Precipitation

• a. Caused by release of SO4-2 NO3- into
  atmosphere by coal burning power plants
• b. SO4-2 NO3- react with H2O to produce
  sulfuric acid, H2SO4 nitric acid, HNO3
• c. Acid precipitation results in leaf damage,
  dead lakes, fish kills

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4. Invasive Species

• a. Zebra mussels, round goby, phragmites,
  dandelion, rusty crayfish, signal crayfish, brown
  trout, rainbow trout . . .
• b. Foreign species lack predator parasite
  control and out compete, displace, replace
  native species
• c. Unified Neutral Theory of Biogeography

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c. Unified Neutral Theory of Biogeography

• 1.) Species should not be moved around the globe
• 2.) But once introduced, they compete like any
  other organism
• 3.) If they establish, ecosystem will adjust
• 4.) We may not like the adjustment, but
  attempting removal is most likely pointless a
  waste of time money

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