Coral Reefs

Question 1

What are nematocysts

Answer 1

they are used to capture prey, and as defense and to compete for space
the polyp is enclosed in calcium carbonate created by the coral

Question 2

Hermatypic corals

Answer 2

reef builders
normally contain zooxanthellae, symbiotuc photosynthetic dinoflagellates
restricted in distrubution by water temperature and water quality

Question 3

Ahermatypic corals

Answer 3

do not build reefs
may not contain zooxanthellae
not restricted by water temp and quality

Question 4

coral reefs are groups of _____ ______ interconnected by ___ ______ __ ______

Answer 4

coral polyps
thin layers of tissue

Question 5

they share a _______ ______ and _________ __________ due to the fact that the entire colony came from _________________________

Answer 5

nervous system and digestive connection
one original polyp that reproduced asexually

Question 6

each polyp continues to ______________________ so the colony continues to grow _______

Answer 6

lay down new CaCO3 beneath beneath the polyp body
upward

Question 7

what is the zooanthelae symbiotic relationship with the coral

Answer 7

• the zooxanthellae provide organic molecules to the corals
• the corals provide carbon dioxide, nitrogen and phosphorus for the zooxanthellae

Question 8

some corals can produce ________________ to capture ___________________

Answer 8

sheets of mucous
zooxanthellae or detritus

Question 9

what are mesenterial filaments

Answer 9

extensions in the gut wall used for feeding

Question 10

conditions required for reef growth

Answer 10

• hard substrate
• Light optimal
• Narrow temperature range
• Low sediment load in water
• Low pollution
• Narrow range of pH

Question 11

How do corals reproduce asexually

Answer 11

buds grow from a single polyp

Question 12

How do they reproduce sexually

Answer 12

creation of a planula larvae that is able to ride on the water currents to a new environment

Question 13

Where the corals at

Answer 13

mostly found on contenential shelves, near islands or on seamounts due to the light/depth dependency

Question 14

Temp requirements

Answer 14

• hermatypic only tolerate low temps
• can only reproduce if over 68d F
• high temps for optimal growth
• above 86 bad

Question 15

What does coral stress cause

Answer 15

“bleaching”: an expulsion of zooxanthellae from the coral polyp
makes the coral white and KILLS it

Question 16

What causes bleaching

Answer 16

poor water quality
increased sediment in water column
wave stress
low salinity
disease
- El Nino, Hurricanes

Question 17

Salinity requirements

Answer 17

35 ppt
not near rivers

Question 18

why wave action bad

Answer 18

suspends sediments in the water, settles on corals, reduces water clarity - reduces photosynthesis

Question 19

Tall vs flat

Answer 19

tall: shallow areas due to intense competition for space and light
wide ; deeper areas to capture as much light as possible

Question 20

what else builds reefs?

Answer 20

coralline algae
cnidarians
sponges
Bryozoans

Question 21

Fringing Reefs (moana)

Answer 21

• simplest and most common
• narrow stripes along the shore in tropical waters
• consist of an inner reef flat and an outer reef slope
• steep, not exposed to air
• high growth, more species on the slope and the crest
• high wave action

Question 22

Barrier reef

Answer 22

• grow along along or farther from the shore
• lagoon between the shore and the reef
  waves wash sediment onto the back reefs slope reducing coral growth
• small islands called keys or cayes
• more growth in crest or just below on the fore-reef

Question 23

The largest reef in the world

Answer 23

The Great Barrier Reef in Australia
- length of reef structures: 1200 miles
- width: 10-200 miles

Question 24

what is an Atoll

Answer 24

a circular reef structure surrounding a central lagoon

Question 25

when do Atolls form

Answer 25

when a volcanic island is formed:
over time, weathering and geologic activity lowers the level of the island till it disappears below the waters surface, leaving only the outer band of coral surrounding a lagoon

Question 26

two largest atolls

Answer 26

Maldives (Indian ocean)
Marshall islands (pacific)

Question 27

Coral reef ecosystems foodchain is based on

Answer 27

Zooxanthellae located in the body of the corals

Question 28

What do Cyanobacteria do for the reef organisms?

Answer 28

they fix nitrogen, making it available to the organisms that feed on them

Question 29

what part of corals do reef organisms feed on?

Answer 29

the corals themselves
mucous
eggs
larvae

Question 30

how do reef organisms deter predation?

Answer 30

• release toxic or foul tasting chemicals
• produce hard (spikey?) structures
• Coralline algae grow in a very thin encrusting form that is difficult to feed upon

Question 31

Competition methods

Answer 31

• grow fast and upright to maximize reproductive ability
• grow slow and huge to outcompete others in the long run
• sting each other