The correct answer is Starfish.
Key Points
- Keppel Island is located in the Southern Great Barrier Reef.
- Coral bleaching occurs when reef-building corals shed their tiny algae to relieve stress and to increase their chances of survival.
- A primary cause of coral bleaching on the Great Barrier Reef during summer is heat stress resulting from high sea temperatures and increased UV radiation.
- A temperature increase of just one degree Celsius for only four weeks can trigger bleaching.
- Deprived of their food source, corals begin to starve once they bleach.
- Another major reason for bleaching in Keppel Island is Starfish whose population has grown uncontrollably in this region.
- Normally, the starfish contribute to the reef's diversity by eating faster-growing coral species, which allow for slowergrowing species to thrive.
- But at outbreak levels, the starfish are able to eat coral, a polyp that builds the limestone reefs on which they communally live, faster than the coral can reproduce.
- This causes stress on the corals and leads to bleaching.