Midterms

• Environmental Science and Engineering


  Field of science that studies the interactions of the physical, chemical, and biological components of the environment and the relationship and effects of these components with the organisms in the environment
• Environmental Science and Engineering


  • Brings together the fields of ecology, biology, zoology, oceanography, atmospheric science, soil science, geology, chemistry, and more in an interdisciplinary study of how natural and man-made processes interact with one another and ultimately affect the various biomes of Earth
• Ecology


  Study of the relationships among organisms and their environment
• Levels of Organization

  • Biosphere
  • Biome
  • Ecosystem
  • Community
  • Population
  • Organism/individual
• Biome


  A major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there
• Terrestrial Biomes

  • Desert
  • Grassland
  • Savanna
  • Rainforest
  • Deciduous forest
  • Taiga
  • Tundra
• Terrestrial biomes are responsible for providing food for living organisms, release of O and absorbing CO2
• Aquatic Biomes

  • Ocean
  • Estuary
  • Freshwater
  • Coral reefs
  • Kelp forests
• Aquatic biomes are responsible for providing a home for fish species and regulation of water and climate
• Ecosystem


  Includes both living (biotic) and non-living (abiotic) factors
• Biotic components of an ecosystem

  • Plants
  • Animals
  • Fungi
  • Bacteria
• Abiotic components of an ecosystem

  • Moisture
  • Temperature
  • Wind
  • Sunlight
  • Soil
  • Rocks
• Keystone Species


  Have an unusually large effect on its ecosystem
• Biogeochemical Cycles


  Cycles of water, carbon, nitrogen, phosphorus, and sulfur through the environment
• Water (Hydrological) Cycle

  1. Water from the land and oceans enters the atmosphere by evaporation or sublimation, where it condenses into clouds and falls as rain or snow

  2. Precipitated water may enter freshwater bodies or infiltrate the soil

  3. The cycle is complete when surface or groundwater reenters the ocean
• Carbon Cycle

  1. Carbon dioxide gas exists in the atmosphere and is dissolved in water

  2. Photosynthesis converts carbon dioxide gas to organic carbon, and respiration cycles the organic carbon back into carbon dioxide gas

  3. Long-term storage of organic carbon occurs when matter from living organisms is buried deep underground and becomes fossilized

  4. Volcanic activity and, more recently, human emissions bring this stored carbon back into the carbon cycle
• Nitrogen Cycle

  1. Nitrogen enters the living world through free-living and symbiotic bacteria, which incorporate nitrogen into their organic molecules through specialized biochemical processes

  2. Certain species of bacteria are able to perform nitrogen fixation, the process of converting nitrogen gas into ammonia (NH3), which spontaneously becomes ammonium (NH4 +)

  3. Ammonium is converted by bacteria into nitrites (NO2 −) and then nitrates (NO3 −)

  4. Nitrogen-containing molecules are used by plants and other producers to make organic molecules such as DNA and proteins

  5. Human activity can alter the nitrogen cycle by the combustion of fossil fuels, which releases different nitrogen oxides, and by the use of artificial fertilizers in agriculture, which are then washed into lakes, streams, and rivers by surface runoff
• Phosphorus Cycle

  1. Phosphorus is a major component of nucleic acids and phospholipids, and, as calcium phosphate, it makes up the supportive components of our bones

  2. Phosphorus is also reciprocally exchanged between phosphate dissolved in the ocean and marine organisms

  3. Weathering of rocks and volcanic activity releases phosphate into the soil, water, and air, where it becomes available to terrestrial food webs

  4. Phosphate enters the oceans in surface runoff, groundwater flow, and river flow

  5. Phosphate dissolved in ocean water cycles into marine food webs

  6. Some phosphate from the marine food webs falls to the ocean floor, where it forms sediment
• Sulfur Cycle


  1. Sulfur is an essential element for the molecules of living things

  2. Atmospheric sulfur is found in the form of sulfur dioxide (SO2), which enters the atmosphere from the decomposition of organic molecules, volcanic activity and geothermal vents, and the burning of fossil fuels by humans

  3. Sulfur dioxide from the atmosphere becomes available to terrestrial and marine ecosystems when it is dissolved in precipitation as weak sulfuric acid or when it falls directly to Earth as fallout

  4. The weathering of rocks also makes sulfates available to terrestrial ecosystems

  5. The decomposition of living organisms returns sulfates to the ocean, soil, and atmosphere

  6. The burning of large quantities of fossil fuels, especially coal, releases larger amounts of hydrogen sulfide gas into the atmosphere, creating acid rain which damages the natural environment
• Hydrology


  Study of water, the science that encompasses the occurrence, distribution, movement, and properties of the waters of the earth and their relationship with the environment within each phase of the hydrologic cycle
• Surface Water Hydrology


  Focuses on the distribution of water on or above the earth's surface, encompasses all water in lakes, rivers, and streams, on land and in air, describes the movement and conservation of water on earth
• Surface Water Hydrology Processes

  • Evaporation
  • Transpiration
  • Precipitation
  • Evapotranspiration
  • Surface runoff
  • Overland flow
  • Direct runoff
  • Interflow
  • Infiltration/Percolation
• Groundwater Hydrology


  Deals with the distribution of water in the earth's subsurface, geological materials, such as sand, rock, and gravel
• Zones of Aquifers

  • Unsaturated zone/ vadose zone/ zone of aeration
  • Saturated zone/ phreatic zone/ zone of saturation
• Unconfined Aquifer


  The water table is the upper surface of the zone of saturation in aquifers that are not confined by impermeable geologic material, the infiltration and migration process, renewing groundwater supply, is referred to as recharge
• Perched Aquifer


  Lens of water held above the surrounding water table by an impervious geologic layer, such as bedrock or clay
• Confined Aquifer


  Aquifers bounded both above and below the saturated zone by impermeable layers
• Aquiclude


  Essentially impermeable to water flow
• Aquitard


  Less permeable
• Artesian Aquifer


  Water in the aquifer is under pressure, the water may flow to the surface of the ground due to the impermeable nature of confining layers or elevation differences in the aquifer
• Water Pollution


  Contamination of water bodies with substances that make the water unfit for its intended use
• Sources of Water Pollution

  • Point sources (domestic sewage, industrial waste)
  • Non-point sources (urban and agricultural runoff)
• Acid rain is corrosive rain caused by rainwater falling to the ground through sulfur dioxide gas, turning it into weak sulfuric acid, which causes damage to aquatic ecosystems and the man-made environment
• Other organic chemicals

  • Hydrocarbons from combustion processes and oil and gasoline spills
  • Solvents used in dry cleaning and metal washing
• Arsenic


  Occurrence in groundwater is largely the result of minerals dissolving naturally from weathered rocks and soils, mainly from iron oxides or sulfide minerals
• Toxic metals

  • Cadmium
  • Chromium
  • Copper
  • Nickel
  • Lead
  • Mercury
• Toxic metals


  Heavy metals which enter through discharge of industrial waste and wastewater treatment plants, storm-water runoff, mining operations, smokestack emissions and other diffuse sources
• Heat


  Waters released by many processes such as electric power industries are much warmer than the receiving waters
• Nanoparticles

  Dimension: less than 100 nm
• Water quality management


  Science of knowing how much waste is too much for a particular water body; to know how much waste can be tolerated/assimilated by a water body