EAR - Stresses, nature, rate and responses

Question 1

What are the 4 (2 category) factors that determine the severity of stress events?

Answer 1

Anthropogenic or natural and catastrophic or gradual

Question 2

What is an example of a resilience phase in the GBR

Answer 2

Coral mass spawning events/changes in coral composition, and eventually heat resistant coral species

Question 3

What are reasons for human-induced modifications?

Answer 3

Economic reasons or population pressures

Question 4

What are some examples of human modifications to energy flows?

Answer 4

• Hunting
• Fishing
• Pesticide use
• Ecosystem simplification (e.g. monocultures)

Question 5

What are some examples of human modifications to nutrient cycling?

Answer 5

• Fertiliser use
• Bioaccumulation
• Groundwater removal

Question 6

What are some examples of human modifications to biophysical interactions?

Answer 6

• Topsoil erosion
• Sediment removal
• Climate change
• Ecosystem replacement
• Ocean acidification

Question 7

How does the TRHS respond to natural stress

Answer 7

• Emergent tree falls are common.
• The forest floor is well equipped with decomposers.
• The typical succession processes of rainforests are present following landslides, volcanic eruptions or tsunami damage

Question 8

How can tropical storms and cyclones affect the GBR

Answer 8

• Mechanical damage
• Freshwater pooling (lessens salinity)
• Sediment stirred up from the sea floor
• More runoff (higher turbidity)
• Cyclones usually only affect part of the reef, increases resilience since coral spawning can regenerate these areas

Question 9

How does the GBR respond to natural stresses

Answer 9

1. Bleaching is a significant threat to reef health - Increased frequency of events (5 since 2000 and 4 in the last 6 years).
2. Crown of Thorns starfish outbreaks - Outbreaks due to combinations of currents, predator numbers, decreased water quality
3. Mass spawning events - Currents make some reefs more important for conservation purposes.

Question 10

What are human impacts that affect nature and rate of change in the GBR

Answer 10

• Climate Change (Marine heatwaves and extreme weather)
• Water quality (Temperatures, Turbidity, Chemistry (Acidification, Oxygenation, Salinity))
• Pollution (agricultural runoff)
• Development
• Food chain/ecological disruptions