Lecture 28: Resource Cycle Flashcards
-Introduction to Earth's Resources -Resource Management -Renewable Resources and Use Impacts
Where do humans take materials from?
- The biosphere (hunting, gathering, logging, agriculture)
- The hydrosphere (water, fishing, salt)
- The geosphere (mineral, fuels, building materials)
- The atmosphere (oxygen)
Where are some waste products that are returned?
- The lithosphere (solid waste)
- The hydrosphere )(dissolved material)
- The atmosphere (gases, aerosols)
What are renewable resources?
Those replenished by new growth each season, including food crops, wood, running water, fisheries
What are non-renewable resources?
Those replenished only on longer timescales, including most minerals, fossil fuels, etc.
How was the environment viewed as an open system?
Extraction of seemingly limitless resources and disposal of wastes and by-products directly back.
What caused the strain on Earth’s resources?
The advance of technology which allowed the increase of the human population
How is the Earth actually a closed system?
Wastes and by-products returned from extraction, production, manufacturing, and consumption directly impact the human economy.
How can we manage non-renewable resources?
Through conservation, reuse, recycling, or substitution.
The idea is to use at a rate that does not exceed the replenishment rate
What percentage of forests are natural and what percent are plantations?
95% are natural
5% are plantations (harvested for timber)
Why are forests important?
They directly link the biosphere to the hydrosphere, geosphere, and atmosphere
What are some examples of resources that forests provide?
Timber, latex, nuts, fruits, and oils.
They also host numerous species that could be critical in the development of medicines and other products
What were the consequences of clear-cutting of forests?
- Loss of the root system that hold soils together
- Caused widespread soil erosion, nutrient loss, and accumulation of debris in adjacent streams and rivers
What are two modern methods of harvesting forest?
1) Cut blocks - smaller clear-cut areas surrounded by forest
2) Selective harvesting (thinning) - only trees of certain maturity are removed, and to a level that will prevent ecosystem damage
What are some consequences deforestation?
- Loss in carbon storage in the atmosphere
- Loss in biodiversity
- Could lead to the loss of a habitat of a rare plant which could lead to the extinction of said plant
What is the importance of fisheries?
They are a critical source of animal protein.
-Approximately 3/4 of the total population goes to food supply , while the remainder goes to produce oils or fishmeal for animal consumption
What are two methods of fishery production?
1) Capture fisheries - those in which fish are caught in the wild.
2) Aquaculture - the raising of fishery resources in captivity
What is a consequence of capture fisheries?
Overexploitation
What is a consequence of aquaculture?
Requires considerable resources to run, and can lead to the spread of disease in the fish population.
What are some fishery sustainability concerns?
- Overharvesting
- Pollution
- Climate change
What is commercial extinction?
The depletion of a species due to fisheries to the point where fisheries can no longer make a profit.
What is arable soil?
Soil suited for agriculture - is essential to the global food supply
How do soils form?
They form due to the physical, biological and chemical weathering of underlying parent rock
What is a soil profile comprised of?
Several horizons, starting with the weathered parent rock (C-horizon) and ending with the organic-rich O-horizon
What are the threats to soil resources?
- The loss of nutrients due to overproduction, contamination from agricultural pesticides, herbicides, industrial activities, over-fertilization, and erosion
- Compaction
How can we minimize soil erosion?
- By employing proper crop rotation techniques
- Preventing soil pollution
- Terracing on sloped land
- Optimizing irrigation, pesticide, herbicide, and fertilizer applications
What are the consequences of over-fertilization?
Excess nutrients leach from agricultural fields to freshwater bodies which causes algae, plankton, and aquatic weeds to grow.
-As these organisms die, the process consumes oxygen in the water causing the water to go anoxic. This kills other organisms living in the water
What are some broader impacts of soil degradation and loss?
- Reduced crop yield and income, which in turn jeopardies health and reduces cognitive and health potential
- Less food is produced per unit land
- Limit the available land for growing crops
- Higher lead = lower IQ in children
- Higher calcium = kidney dysfunction, bone disease and cancers
- Higher mercury = neurological damage
How is water used other than for direct consumption?
- Food production
- Used in energy generation
- Transportation (waterways for boats)
- Recreation
- Industrial processes
What is the largest consumer of water?
Irrigation.
- Comprises more than 75% of use
- Most of the water rapidly returns to the hydrologic cycle
What is water stress?
The demand vs supply in a region of the world
How do dams contribute to the consumption of water?
- Water is rerouted for agriculture and industrial purposes
- Generate energy
What are the consequences of dams?
- Habitat loss
- Modification of river ecosystems
- Modifications to seasonal discharge rates and patterns
- A reduction in sediment transport downstream
What is a consequence of diversions?
Overconsumption of a water supply which causes that body of water to dry up.
What is a consequence of groundwater mining?
If the pumping rate exceeds the rate of recharge (which is the case for many areas of the world) physical and chemical changes may occur to the properties of aquifers.
-Permanent loss of porosity and increagly saline groundwater
