Rocky and coral reefs

Question 1

Hermatypic corals

Answer 1

Reef-building
Secrete CaCO3
Colonial and large number of zooxanthellae
Divided in: massive and brancing forms

Question 2

Ahermatypic corals

Answer 2

Non-reef building

Worldwide and in deep sea

Question 3

Factors limiting reef growth

Answer 3

Temperature
Light availability
Salinity
Turbidity
Sedimentation
Sea level fluctuation
Bioerosion by grazers and borers

Question 4

Coastal reefs are divided into:

Answer 4

Fringing reef
Patch reef
Barrier reef

Question 5

Barrier reef

Answer 5

Typical in tropical islands and are separated from coast by a lagoon.
Fast growth in lower zone

Question 6

Fringing reef

Answer 6

Common in beaches where rocks are available for coral growth

Grow up to the surface and then extend horizontally

Question 7

Patch reef

Answer 7

Common in lagoons

Question 8

Atolls

Answer 8

Explosive volcano disappears and contour remains, which is filled by water, forming a lagoon

Question 9

Coral reef growth upset by:

Answer 9

Climate change
sedimentation
fishing
pollution

Question 10

Rocky reefs are divided into:

Answer 10

Intertidal and subtidal zone

Question 11

Rocky reef intertidal zone is dominated by

Answer 11

Individuals (mussels, barnacles, limpets)

Question 12

Subtidal zone is dominated by:

Answer 12

Colonial animals

But also include individual species

Question 13

Colonial forms are more common in subtidal zone because:

Answer 13

Do not have the ability to live without water (dessication)
Do not tolerate salinity differences
More resistant to predation and competition

Question 14

Competitive interactions properties:

Answer 14

Space occupation
Rapid growth
Larger colonies are more competitive
Unpredictable outcomes due to varied competitive mechanisms
Priority effect on bare surfaces

Question 15

Why do rocky reefs have a nursery function?

Answer 15

Junvenile fishes can grow

Food availability and protection from predators

Question 16

Why do rocky reefs have a nursery function?

Answer 16

Junvenile fishes can grow

Food availability and protection from predators

Question 17

What determines prominent depth zonation?

Answer 17

Wave and current strength, light and suspended sediments

Competition: dominance and overgrowth

Question 18

What is mutualism?

Answer 18

symbiotic relationship where all species involved benefit from their interactions

Question 19

Predation defense of coral reefs

Answer 19

1) Chemical defenses

2) Camouflage or nocturnal activity

Question 20

What are the main biological interactions and community structure of coral reefs?

Answer 20

1) Higher complexity and diversity of competition slows down dominance of one species
2) Herbivores have strong effect on species composition
3) Strong top-down effects (predator controls abundance of rest of the species)

Question 21

What are major threats to coral reefs?

Answer 21

1) Human impact
2) Direct: sedimentation, pollution, diseases, tropical storms
3) Indirect: increased nutrients and overfishing, climate change
4) Thermal stress can cause mass bleaching

Question 22

Reefs and human society

Answer 22

1) Source of food and income
2) Economic benefit but also anthropogenic stress
3) ecosystem service: coastal defense