Coral Reefs

Question 1

where are corals distributed?

Answer 1

Very diverse in Indo-Pacific (stable temperature and water levels) & Atlantic - 25N and 25S are tropical reefs; others are cold water

Question 2

coral triangle? this is in malasia, indonesia etc area, look at map

Answer 2

riches in Coral Triangle
Sedimentation & Glaciation affects most
- local sp. Richness relates to regional (evolutionary history and biogeographical conditions)

• most stable sea levels (coral triangle)

Question 3

atoll reefs? look at diagram of darwins theory of atolls origin

Answer 3

• Atolls: open ocean island chains, cap volcanic islands (extinct) - Pacific & Caribbean - windward (towards wind) & leeward (away from wind) sides
• -Some species grow more in windward sides (wind/current = more growth): too much can destroy
An atoll is a ring-shaped coral reef, island, or series of islets. An atoll surrounds a body of water called a lagoon.

Question 4

costal reefs?

Answer 4

• Coastal: large fringing platform, grows away from continent and buffers it from erosion (continental shelf, ex. Great Barrier Reef).

Question 5

captive coral tanks?

Answer 5

Captive Coral Tanks (mini-reef systems): Has tufa, extinct rock, live rock. Use LED light to grow. Smaller you fragment a coral, they will grow faster (possibly stress/chemical reaction).

Question 6

coraline algae?

Answer 6

Coraline Algae: base building (rock substrate) protist to reef system

Question 7

aritificial reefs?

Answer 7

• Artificial Reefs: ex. Sunken ships, bio-rock.

sometimes made of plastic

Question 8

depth zonation of reefs? why/describe

Answer 8

successive zones of dominate corals (different diversities/species in zones). - Some corals can grow in more than one region
results from: a. wave & current strength b. light & suspended sediment.

Question 9

zonation levbels

Answer 9

massive corals deeper, heavy branching corals mid, small corals in pools and channels near top

Question 10

Buttress or Breakwater Corals

Answer 10

Buttress or Breakwater Corals: Large corals at reef fronts that keep erosion at bay and keep the reef intact. Breaks wave activity.

Question 11

coral phyla? what are scleractinia?

Answer 11

• Phylum Cnidaria

- Scleractinia (Also called LPS – large polyp stony: hard corals)

Question 12

Scleractinia? Defense mechanism?

Answer 12

Scleractinia (Also called LPS – large polyp stony: hard corals):
○ CaCO3 secretion (reef builders), most colonial with polyps,
Polyps retract as defense mechanism (animal, strong current)

Question 13

corallite?

Answer 13

○ corallite = skeletal unit of each polyp

in scleractinian coral

Question 14

hematypic coral?

Answer 14

Hermatypic Corals: calcify at high rates, high [zooxanthellae]: 2 subtypes (massive & branching).

Question 15

• Zooxanthellae? where do they live? what happens to them in coral when bleaching occurs?

Answer 15

Zooxanthellae (Colloquial term): - dominant Symbiodinium genus of dinoflagellates - live in endodermal tissue in vacuoles (mostly tentacles) - gives color
• also in other inverts (ex. Squid) - ~8 major clades, only 4 in coral* - They are taken up and expelled -
• Bleaching: stress reaction (zooxanthellae die)

Question 16

benefits of zooxananthellae to coral

Answer 16

• Benefits to Coral = 
		○ a. remove waste    
		○ b. provide O2    
		○  c. make carbs   
		○   d. enhance calcification     
		○ e. aid lipid synthesis

Question 17

benefits of coral to zoozanthellae

Answer 17

• Benefits to Zooxanthellae =
○ a. predator protection
○ b. access to coral nutrients
• *Controversial: No way to actually identify them (scientists constantly argue)

Question 18

types of coral reproduction? gamete production?

Answer 18

• Coral Reproduction: hermaphroditic & separate sexes.
• - Gamete Production = - internal fertilization & release of planula (free-swimming) larvae
○ broadcast spawning

Question 19

cues of reproduction for coral?

Answer 19

○ a. moon cycles & night
○ b. seasonal july mass spawns (100+spp.)
• Never during the day
• Very consistent timing
• Linked to species - ie if species A spawns at 1:10, species b next at 1:30

Question 20

why mass spawning?

Answer 20

○ Increase chances of fertilization - lots of gametes = increased chance, especially with sperm conc. - bc of sperm age - does not remain viable for only a short period of time - cant expect that they will remain around

Question 21

how can zooxanthellae be seen?

Answer 21

mmunofluorescence microscope - shown in documentary
• Attach flur. Antibodies in other organisms - in coral it can just be put under on its own bc natural flur.
• Confocal microscopy - hitting w high intensity blue wave lengths
• Only images coral and symbionts - endosymbiotic algae on the coral - choloro. Flurs.
• Blue and green colors = corals flur.

Question 22

confocal microscopy?

Answer 22

• Confocal - eliminates light from outside the scope
  
  • Z stacking- takes pics of all of the planes - assembles them into a 3d image - see whole organism- or animations
  • Red = chloro flur. From symbiodinium
  • Blue = stinging cells
  • Symbiodinium arrangement can be seen as well as coral cells
  • Filament to battle neighboring coral or expel symbiodinium
  • Associated epifauna identified
  • Coral larvae - especially if rooted
  • As temps rise, they lose the symbiont = bleaching, weak coral

Question 23

Why so many spp. In the same evening?

Answer 23

○ Buffet for fish and invertebrate - eat gametes until their full - mass spawning event prevents fish from eating them all - overwhelm predators
○ Also neap tides (low waves) - high current - gametes moved in water column
Could also be coincidental - no cross breeds - just all lined up bc of neap tides and moon cycle

Question 24

larvae recruitment? why?

Answer 24

• Planulae recruit back to reef or move offshore
• More likely to settle in an area where there are parental - reef - or move offshore - more challenging for survival
• Called recruitment (back to the reef system) - recruitment is a function of:
○ Amount of reproduction
○ Strom/current conditions

Question 25

is recruitment successful?

Answer 25

yes
§ Local genetic differences even with long distance dispersal (ie new recruits coming into the area)
○ Reef system can still recruit actively - comes down to local comp - what variability is already established

Question 26

• Local differentiation from regional natural selection or genetic drift?

Answer 26

○ Mainly natural selection through strong localized selection - makes species dominant in that area - strong selection for locally dom species - new species coming in struggle
○ Counters inappropriate genotypes - not favorable genotypes - gets out competed if there

Question 27

can reefs survive out of water?

Answer 27

• Some reef systems exposed at low tide - can still survive for hours in the temp + out of water
•

Question 28

gamete production types?

Answer 28

nternal fert. And release of planula larvae
• 1st possibility -Kept in tissue/on parents then released
• 2nd- Can also have broad cast spawning- release gametes into the ocean
• Grouped by species - differ in which method they use
○ Self - fertilize - lower genetic variability - usually just release gametes
○ Ex. Rice coral - broadcast spawning - bring in specimens and let them spawn- then collect gametes and study the biological affects - Montipora spawning at HIMB (tank specimens)

Question 29

why can we collect coral gametes easy?

Answer 29

○ Gametes are positively buoyant
○ Can collect specimens as they rise to the surface
○ We can also freeze the gametes and maintain coral banks

Question 30

asexual reproduction pro/con

Answer 30

○ Less variability but release more = lots of corals