Lecture 28: Resource Cycle

Question 1

Where do humans take materials from?

Answer 1

• The biosphere (hunting, gathering, logging, agriculture)
• The hydrosphere (water, fishing, salt)
• The geosphere (mineral, fuels, building materials)
• The atmosphere (oxygen)

Question 2

Where are some waste products that are returned?

Answer 2

• The lithosphere (solid waste)
• The hydrosphere )(dissolved material)
• The atmosphere (gases, aerosols)

Question 3

What are renewable resources?

Answer 3

Those replenished by new growth each season, including food crops, wood, running water, fisheries

Question 4

What are non-renewable resources?

Answer 4

Those replenished only on longer timescales, including most minerals, fossil fuels, etc.

Question 5

How was the environment viewed as an open system?

Answer 5

Extraction of seemingly limitless resources and disposal of wastes and by-products directly back.

Question 6

What caused the strain on Earth’s resources?

Answer 6

The advance of technology which allowed the increase of the human population

Question 7

How is the Earth actually a closed system?

Answer 7

Wastes and by-products returned from extraction, production, manufacturing, and consumption directly impact the human economy.

Question 8

How can we manage non-renewable resources?

Answer 8

Through conservation, reuse, recycling, or substitution.

The idea is to use at a rate that does not exceed the replenishment rate

Question 9

What percentage of forests are natural and what percent are plantations?

Answer 9

95% are natural

5% are plantations (harvested for timber)

Question 10

Why are forests important?

Answer 10

They directly link the biosphere to the hydrosphere, geosphere, and atmosphere

Question 11

What are some examples of resources that forests provide?

Answer 11

Timber, latex, nuts, fruits, and oils.

They also host numerous species that could be critical in the development of medicines and other products

Question 12

What were the consequences of clear-cutting of forests?

Answer 12

• Loss of the root system that hold soils together

- Caused widespread soil erosion, nutrient loss, and accumulation of debris in adjacent streams and rivers

Question 13

What are two modern methods of harvesting forest?

Answer 13

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

Question 14

What are some consequences deforestation?

Answer 14

• 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

Question 15

What is the importance of fisheries?

Answer 15

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

Question 16

What are two methods of fishery production?

Answer 16

1) Capture fisheries - those in which fish are caught in the wild.
2) Aquaculture - the raising of fishery resources in captivity

Question 17

What is a consequence of capture fisheries?

Answer 17

Overexploitation

Question 18

What is a consequence of aquaculture?

Answer 18

Requires considerable resources to run, and can lead to the spread of disease in the fish population.

Question 19

What are some fishery sustainability concerns?

Answer 19

• Overharvesting
• Pollution
• Climate change

Question 20

What is commercial extinction?

Answer 20

The depletion of a species due to fisheries to the point where fisheries can no longer make a profit.

Question 21

What is arable soil?

Answer 21

Soil suited for agriculture - is essential to the global food supply

Question 22

How do soils form?

Answer 22

They form due to the physical, biological and chemical weathering of underlying parent rock

Question 23

What is a soil profile comprised of?

Answer 23

Several horizons, starting with the weathered parent rock (C-horizon) and ending with the organic-rich O-horizon

Question 24

What are the threats to soil resources?

Answer 24

• The loss of nutrients due to overproduction, contamination from agricultural pesticides, herbicides, industrial activities, over-fertilization, and erosion
• Compaction

Question 25

How can we minimize soil erosion?

Answer 25

• By employing proper crop rotation techniques
• Preventing soil pollution
• Terracing on sloped land
• Optimizing irrigation, pesticide, herbicide, and fertilizer applications

Question 26

What are the consequences of over-fertilization?

Answer 26

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

Question 27

What are some broader impacts of soil degradation and loss?

Answer 27

• 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

Question 28

How is water used other than for direct consumption?

Answer 28

• Food production
• Used in energy generation
• Transportation (waterways for boats)
• Recreation
• Industrial processes

Question 29

What is the largest consumer of water?

Answer 29

Irrigation.

• Comprises more than 75% of use
• Most of the water rapidly returns to the hydrologic cycle

Question 30

What is water stress?

Answer 30

The demand vs supply in a region of the world

Question 31

How do dams contribute to the consumption of water?

Answer 31

• Water is rerouted for agriculture and industrial purposes

- Generate energy

Question 32

What are the consequences of dams?

Answer 32

• Habitat loss
• Modification of river ecosystems
• Modifications to seasonal discharge rates and patterns
• A reduction in sediment transport downstream

Question 33

What is a consequence of diversions?

Answer 33

Overconsumption of a water supply which causes that body of water to dry up.

Question 34

What is a consequence of groundwater mining?

Answer 34

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