5.7-5.12

• CAFOs

  • Also called feedlots
  • Densely crowded method where animals are fed grain (corn) to raise them to adult as quickly as possible

  
• CAFOs: Pros

  • Maximizes land use and profit (most meat production per unit of area)
  • Maximized cost of meat for consumers (cheaper)

  
• CAFOs: Cons

  • Given antibiotics and growth hormones to prevent disease outbreaks and speed meat production
  • Animals produce large amounts of waste, which can contaminate nearby surface or groundwater
  • Produces large amounts of CO2, CH4 (methane), and N2O (nitrous oxide) (greenhouse gases that lead to climate change)

  
• Manure Lagoons

  • Large, open storage pits for animal waste called manure
  • Waste deposited in bodies of water containing NH4 (ammonium), hormones, antibiotics, fecal coliform bacteria (e. coli)
  • Heavy rain can flood lagoons and contaminate nearby surface and groundwater with all of those dangerous pollutants

  
• E. Coli (Manure Lagoons)

  • Ammonium (nitrogen source) leads to eutrophication
  • Antibiotic and growth hormone alters the endocrine (hormonal system) of humans and amphibians
  • Denitrification of ammonia in manure produces N2O (nitrous oxide -- potent GHG)

  
• Manure Lagoons: Solution

  • Drain lagoon regularly
  • Turn into fertilizer pellets to serve as a useful rather than harmful source

  
• Free Range Grazing

  • Animals (usually cows) graze on grass and grow at a natural rate without hormones

  
• Free Range Grazing: Pros

  • There is no need for antibiotics as the population is dispersed, lowering the chances of disease outbreaks.
  • It doesn't require the production of corn to feed animals
  • Waste is dispersed over land naturally, acting as a fertilizer instead of building up in lagoons

  
• Free Range Grazing: Cons

  • Requires more total land use per pound of meat produced
  • More expensive for the consumer because it takes much more land
• Overgrazing

  • Too many animals grazing an area of land can remove all of the vegetation (grass), which leads to topsoil erosion
  • Animal hooves can also compact soil, decreasing H20 carrying capacity and leading to more topsoil erosion

  
• Desertification

  • This can occur if plants are killed by overgrazing and soil is compacted so much that it can't hold enough water anymore; the soil is not productive anymore

  
• Desertification: Solution

  • Rotational Grazing (moving animals periodically) can prevent overgrazing and allows plants to continue growing
  • Overtime, rotational grazing can increase the growth of grass by distributing manure (natural fertilizer) and clipping grass back to size where growth is most rapid (1/2)

  
• Meat Efficiency

  • Producing meat for humans to eat is far less efficient than producing plants in terms of energy, land use, and water use
• Meat Efficiency: Energy

  • All of the energy needed to plant, grow, and harvest plants to feed animals plus:
  • The energy needed to bring water to animals
  • The energy needed to house animals
  • The energy needed to slaughter and package
• Meat Efficiency: Land

  • All of the energy needed to grow plants to feed animals PLUS the space animals take up
• Meat Efficiency: Water

  • All of the water for crops that animals eat PLUS the water the animals drink
• Fisheries

  • Populations of fish used for commercial fishing
• Fishery Collapse

  • When overfishing causes 90% population decline in a fishery
  • The population may never recover due to decreased biodiversity, inability to find mates, and inbreeding depression
• Fishery Collapse

  • Decreases genetic biodiversity of fish populations and species biodiversity of ocean ecosystems if species are lost from the ecosystem
  • Economic consequences include lost income for fishermen and lost tourism dollars for communities (hotel, restaurants)
• Economic Impact

  • Overfishing from 1975 to 1985 led to sharp loss of profits from 1985-2018
  • Example of Tragedy of the Commons: no incentive or penalty to prevent overfishing from 1975 to 1985
• Bottom Trawling

  • An especially harmful fishing method that involves dragging a large net along the ocean floor

  
• Bycatch

  • Unintended species like dolphins, whales, and turtles caught in nets
  • This method stirs ocean sediment (turbidity) and destroys coral reef structure.
  • As a result, organisms can't perform photosynthesis due to the limited sunlight

  
• Bycatch decreases biodiversity by:

  • Removing coral reef habitat
  • Killing non-target
• Fishing Down and Trophic Cascade

  • As we deplete large, predatory fisheries, we move down to smaller fish species
  • Depletion of smaller fish populations limits fishery recovery and decreases food supply of marine mammals and birds
• Trophic Cascade

  • As smaller fish (secondary consumers) decrease, zooplankton (primary) will increase, decreasing producer populations dramatically
  • Ripple effect
• Ore

  • Commercially valuable deposits of concentrated minerals that can be harvested and used as raw material

  
• Metals

  • Elements that conduct electricity, heat, and have structural properties for buildings (found with ores)
• Reserve

  • The known amount of a resource left that can be mined
  • Usually measured in years left of extraction

  
• Overburden

  • Soil, vegetation, and rocks that are removed to get to an ore and deposit below
• Trailings and Slag

  • Leftover waste material separated from valuable metal or mineral within ore (often stored in ponds or at mine site)

  
• Surface Mining

  • The removal of overburden to access ore near surface
• What are 4 types of surface mining?

  Open pit, strip, placer, mountain top removal
• Open Pit Mining

  • Digging a big pit in the ground, piling overburden on the site

  
• Strip Mining

  • Peeling/digging back layers of overburden

  
• Placer Mining

  • Smaller-scale; using a tool that shakes valuable material to recover

  
• Mountain Top Removal

  • Especially damaging to landscapes and habitats, streams nearby, uses dynamite
  • Destroys habitats

  
• Mountain Top Removal: Consequences

  • Removal of vegetation and soil
  • Topsoil erosion (no plants to hold soil)
• Mountain Top Removal: Consequences

  • Habitat loss (lost soil and vegetation)
  • Increased stream turbidity (sediments carried to nearby waterways)
  • Increased particulate matter (lots of dust from explosion)
  • By far the WORST mining method
• As ore near the surface becomes more scarce, mining moves deeper underground to subsurface mining (more dangerous and expensive)
• Subsurface Mining

  • More expensive due to:
  • Higher insurance and healthcare costs for workers
  • More risky:
  • Poor ventilation leads to toxic gas exposure
  • Mine shaft collapse
  • Injury from falling rock
  • Lung cancer, asbestos, fires, explosions