Coral Reefs Flashcards
Importance of grazing
Grazers eat algae, which can creat competition and take over coral reefs. They prevent algae from turning into macro algae which releases toxins and scents that are unattractive to other organisms. They clear surface space for CCA
What is coral bleaching?
Zoozanthelae leave corals due to stress from warmer waters. Corals can only live for up to 1 month w/o Zoozanthelae.
Coral structures
Branching: fastest growing
Mounding: slowest growing
Encrusting: can grow in cracks
Plating: shades out other corals
How do corals compete for space and sunlight?
They excrete chemicals to keep other corals away from their area. Some will try to shade others out.
Threats to coral reefs
Diseases in corals and grazers Species invasions Human contact (walking) Collection Fishing- w/ nets, dynamite, Overfishing grazers Sedimentation Global warming Ocean acidification Too many nutrients
Benefits of coral reefs
Biodiversity Protects shorelines Source of Primary productivity in habitat Supports coastal communities Revenue, food, tourism
Formation of atols
Corals will form a ring around volcanic island.
Volcanic island cools and sinks, but coral reef remains.
New coral uses dead coral as substrate. Lagoon forms between coral ring and volcano: barrier reef
When volcanic island sinks completely, coral ring forms atoll that is independent of island
What is a barrier reef in corals?
Area of water between coral ring and volcanic island
How do corals get food? When do they feed?
90% from zooxanthelae.
Feed at night for other 10%
What is a barrier reef?
A reef that is a great distance from shore with a deep lagoon
What is the zonation of coral reefs in order from closest to shore+ characteristics?
- Patch reef- smaller corals, high sedimentation
- Reef flat
- Reef crest- wave tolerant, branching corals
- Fore reef- highest biodiversity, high competition. Clear, clean water, more mounding corals.
