Coral reefs and ecosystem connections

What organisms make up coral reefs?

Scleractinian corals - are reef building corals

How do coral colonies form?

Growth of individual polyps through asexual budding and sexual reproduction

What is the role of zooxanthellae in corals?

Symbiotic dinoflagellates provide nutrients through photosynthesis

Name the parts of the coral

Theca, septa, corallite,

Skeleton- costae, corallite

Name the five types of coral - in regards to their shape

Encrusting

Massive

Tabular

Corymbose

Branching

What are the key environmental requirements for coral reef formation?

Warm temperatures (>18°C), clear water, low sedimentation, hard substrate

What are the three main types of coral reefs?

Fringing reefs, barrier reefs, atolls

What is Darwin’s theory of atoll formation?

Volcanic island subsides, leaving behind a ring-shaped coral reef
goes from active volcano, to a volcano with a friging reef, then barrier reef with a lagoon, and then a lagoon.

How does primary production occur in coral reefs?

Turf algae, macroalgae, zooxanthellae, phytoplankton

What are the major threats to coral reefs?

Overfishing, climate change, coral disease, habitat destruction

What are the zones of a reef

Beach - seagrass bed

Reef flat - small coral patches

Reef crest - branching corals (Acropora)

Reef front - Sea - High wave stress, massive corals

compare and contrast indo pacific vs atlantic

Atlantic:

• Younger

• ~62 coral spp

• 3 Acropora spp

• Fragmentation

• Nocturnally active

• Gorgonians, sponges

• 1,200 mollusc spp

• 550 fish spp

Indo pacific:

• Older

• 500+ coral spp

• 200 Acropora spp

• Sex. reproduction

• Diurnally active

• 5,000 mollusc spp

• 2,200 fish spp

what drives primary production in coral reefs?

• Turf algae, macroalgae, zooxanthellae, phytoplankton

• High productivity

• ~2,500 g C m2 yr-1 total (average)

• 400 – 3500 g C m2 day-1 for algae alone

• 20-90% of net algal production eaten

ecosystem services of coral reefs

Coastal protection

Fisheries

Tourism

threats to coral reefs

Fishing

Climate change

Disease

compare waves and nutrients between mangroves, sea grass meadows, and coral reefs

mangrove forests need low wave action, retains sediment, and reduces nutrients

seagrass meadows need low wave action and clear water -