Chapter 11: Coral Reefs

Question 1

What are coral reefs

Answer 1

• constructional wave-resistant features
• built by a variety of species
• often cemented together
• aided by zooxanthellae, symbiotic algae

Question 2

what are the 2 types of corals?

Answer 2

• reef-building or hermatypic corals

- non reef-building or ahermatypic corals

Question 3

what is the temperature range associated with coral reefs?

what are optimal temps?

Answer 3

18-36*C temp range

Optimum temp @ 26-28*C

Question 4

what physiological factors are coral reefs dependant upon?

Answer 4

• underlying substratum
• long-term changes
• light levels
• wave action

Question 5

what are three different large-scale reef constructions?

Answer 5

• Patch
• atoll
• barrier reefs

Question 6

what are bioeroders?

Answer 6

• waves
• grazing fish (parrotfish)
• sea urchins
• sponges
• other forces/organisms
• ->break down coral skeletons into fragments that settle into spaces in the reef structure or form sandy bottoms in associated reef lagoons

Question 7

what do the polyps of hermatypic corals usually contain?

what is their role?

Answer 7

• symbiotic algae or zooxanthellae

- photosynthesize and provide energy for the coral polyp

Question 8

name some benefits for coral in the zooxanthellae symbiosis

Answer 8

• supply of reduced carbon providing low respiration costs and conservation of metabolic resources
• increased growth and reproduction
• increased calcification rate
• conservation of nutrients
• sequestration of toxic compounds by algae

Question 9

name some benefits for zooxanthellae in the coral symbiosis

Answer 9

• supply of CO2 and nutrients from host maintenance in photic zone
• protection from UV damage by animal tissue
• maintenance of a high population density of a single genotype by host under uniform environmental conditions

Question 10

what is the main method of coral reproduction?

Answer 10

simultaneous hermaphrodite, although they can reproduce both sexually and asexually

Question 11

what are the principal coral-affecting factors?

Answer 11

-temp, light, depth, salinity, wave energy, sediment and pollution

Question 12

what are some management priorities?

Answer 12

• erosion control and catchment management
• atmospheric emission control
• development and implementation of fishing regs
• more protected areas

Question 13

what are threats to coral reefs?

Answer 13

• disease
• storms cyclones and hurricane
• climate change
• coral bleaching
• bioerosion
• pollution, sediments, and nutrients
• fishing

Question 14

reef growth is a balance between what two things?

Answer 14

accretion and bioerosion