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Flashcards in Coral Reefs Deck (11)
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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)
Fishing- w/ nets, dynamite,
Overfishing grazers
Global warming
Ocean acidification
Too many nutrients


Benefits of coral reefs

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?

1. Patch reef- smaller corals, high sedimentation
2. Reef flat
3. Reef crest- wave tolerant, branching corals
4. Fore reef- highest biodiversity, high competition. Clear, clean water, more mounding corals.