Global change

Question 1

Nutrient enrichment

Answer 1

Agriculture: Geographic separation between where food is grown and where it is consumed
Disruption of local nutrient cycles
Requires addition of fertiliser to agricultural land
Global increase in nutrients in ecosystems

Question 2

Impacts of nutrient enrichment:

Answer 2

Eutrophication in aquatic ecosystems
Biodiversity loss in terrestrial ecosystems (e.g 1/3rd reduction of plant diversity in British ecosystems

Question 3

Impacts of nutrient enrichment:

Answer 3

Eutrophication in aquatic ecosystems
Biodiversity loss in terrestrial ecosystems (e.g 1/3rd reduction of plant diversity in British ecosystems

Question 4

Most conspicuous eutrophication effect:

Answer 4

Algal blooms, followed by algal die-offs that lead to oxygen depletion

Question 5

Toxins in the environment

Answer 5

Industrial compounds and pesticides -
When toxins not excreted: Biological Magnification
Pharmaceuticals -
Feminisation of male fish due to chemicals with estrogenic properties
Plastic waste -
Mechanical problems: animals ingest plastic and starve
Leaching of chemicals (some with estrogenic properties)

Question 6

Greenhouse gases and climate change -

Answer 6

Increase in CO2 conc in Earth’s atmosphere since industrial revolution
Increase in CO2 leads to global warming through greenhouse effect
Impacts: range shifts, disrupted species interactions, coral bleaching, etc
Also leads to ocean acidification
Impacts: Less calcium carbonate available for building and maintaining calcified structures by organisms
Where CO2 is limiting factor in photosynthesis, increase in plant and algal growth
Depletion of Atmospheric Ozone
Chlorofluorocarbons (CFC) pollution thins layer of O3 in stratosphere that filters UV
Impacts: DNA damage, leading to cancers in humans, reduced growth in phytoplankton, etc.