Unit 8 - Essays - Coral Reefs Flashcards
(4 cards)
Assess the significance of different threats to coral reefs
Assess the significance of different threats to coral reefs
Paragraph 1 – Climate Change and Coral Bleaching (Most significant)
Rising SSTs cause bleaching; expulsion of zooxanthellae leads to coral death.
GBR mass bleaching events in 1998, 2016, 2017, 2020.
50% of shallow northern GBR corals died in 2016.
Paragraph 2 – Sea Level Rise
Corals need light; rising seas may drown reefs.
Since 1900, sea levels have risen 20cm; could rise 1m by 2100.
Atolls (e.g. Maldives) are highly vulnerable; may not keep pace with growth.
Paragraph 3 – Agricultural Runoff and Pollution
Inshore GBR affected by sediment, pesticides from rivers (e.g., Burdekin).
Causes eutrophication, algal blooms, and disease.
Linked to crown-of-thorns outbreaks.
Paragraph 4 – Physical Damage from Tourism and Shipping
Over 2 million tourists annually; anchor damage, trampling.
2010 coal ship grounding damaged 3km² of reef.
Outer reefs less impacted due to remoteness.
Paragraph 5 – Ocean Acidification
CO₂ absorption lowers pH, weakens coral skeletons.
Slows calcification, especially in juveniles.
Less visible but increasingly impactful.
Conclusion – Judgement
Climate change (temperature and acidification) poses the most widespread, systemic, and long-term threat. Human local impacts like pollution are serious but more manageable.
To what extent can the threats to coral reefs be successfully managed?
To what extent can the threats to coral reefs be successfully managed?
Paragraph 1 – Managing Local Pollution and Runoff
Effective regulations can reduce fertiliser and sediment input (e.g., GBR Reef 2050 Plan).
Wet season challenges remain, but runoff is technically manageable.
Paragraph 2 – Tourism Management
Education, zoning, and mooring buoys reduce physical damage.
Sustainable tourism schemes can fund conservation.
Paragraph 3 – Coral Bleaching and Climate Change
Global threat: local efforts can’t control temperature rise.
Some adaptive measures (e.g., breeding heat-tolerant corals) but not a complete solution.
Paragraph 4 – Ocean Acidification and Sea Level Rise
Requires global CO₂ reduction—beyond control of reef managers.
Some resilience strategies (marine protected areas, monitoring) help buffer impacts.
Paragraph 5 – Variation by Reef Type
Isolated reefs (Maldives) have less pollution but are more threatened by sea-level rise.
GBR has better funding and monitoring but faces multiple threats.
Conclusion – Judgement
Local threats (pollution, tourism) can be managed well; global threats (climate change, acidification) require international cooperation and are harder to control. Management is partially but not fully successful.
‘Some coral reefs are under greater threat than others.’ How far do you agree with this view?
‘Some coral reefs are under greater threat than others.’ How far do you agree with this view?
Paragraph 1 – Greater Threats to Inshore and Shallow Reefs
Inshore GBR faces sediment and nutrient runoff.
Shallow reefs bleach more easily due to higher temperatures.
Paragraph 2 – Geographical Vulnerability
Atolls (e.g. Maldives) are just 1–2m above sea level—highly vulnerable to sea level rise.
Barrier reefs may be more robust due to vertical growth potential.
Paragraph 3 – Anthropogenic Pressure
GBR tourism and shipping intensity = greater localised damage.
Red Sea reefs face less tourism but some port pollution.
Paragraph 4 – Natural Variation in Resilience
Red Sea corals tolerate higher salinity; may be more resilient.
Some outer GBR reefs less affected due to isolation.
Paragraph 5 – Management Differences
GBR has extensive monitoring and global support.
Atolls in LICs may lack funding and adaptive capacity.
Conclusion – Judgement
Clear evidence that threats vary spatially and by reef type. Some reefs (e.g. atolls, inshore GBR) are more vulnerable due to both physical and human pressures.
‘The characteristics and formation of different types of coral reefs are very similar.’ How far do you agree?
‘The characteristics and formation of different types of coral reef are very similar.’ How far do you agree?
Paragraph 1 – Similar Formation Requirements
All need warm (23–29°C), shallow, clear, oligotrophic water.
Require firm substrate and good light for photosynthesis.
Similar biological processes (symbiosis with zooxanthellae).
Paragraph 2 – Differences in Characteristics
Fringing reefs: close to coast, narrow/no lagoon (e.g. Red Sea).
Barrier reefs: large lagoons, complex zonation (e.g. GBR).
Atolls: ring-shaped, central lagoon, formed from subsided volcanoes (e.g. Maldives).
Paragraph 3 – Differences in Formation Processes
Fringing reefs grow directly on coastline rock.
Barrier reefs grow as sea level rises and island subsides.
Atolls represent final stage of subsidence and reef growth.
Paragraph 4 – Distribution and Geomorphology
Barrier reefs form on broad continental shelves (e.g., GBR).
Fringing reefs in narrow steep zones (Red Sea).
Atolls in deep oceanic islands (Maldives).
Paragraph 5 – Variation in Vulnerability
Atolls are extremely low-lying, sensitive to sea level rise.
GBR faces runoff, Red Sea reefs adapted to high salinity.
Conclusion – Judgement
While environmental conditions for coral growth are similar, formation and characteristics vary significantly across reef types. The statement is only partly true.
