Coral Reefs Flashcards
where are corals distributed?
Very diverse in Indo-Pacific (stable temperature and water levels) & Atlantic - 25N and 25S are tropical reefs; others are cold water
coral triangle? this is in malasia, indonesia etc area, look at map
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)
atoll reefs? look at diagram of darwins theory of atolls origin
• 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.
costal reefs?
• Coastal: large fringing platform, grows away from continent and buffers it from erosion (continental shelf, ex. Great Barrier Reef).
captive coral tanks?
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).
coraline algae?
Coraline Algae: base building (rock substrate) protist to reef system
aritificial reefs?
• Artificial Reefs: ex. Sunken ships, bio-rock.
sometimes made of plastic
depth zonation of reefs? why/describe
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.
zonation levbels
massive corals deeper, heavy branching corals mid, small corals in pools and channels near top
Buttress or Breakwater Corals
Buttress or Breakwater Corals: Large corals at reef fronts that keep erosion at bay and keep the reef intact. Breaks wave activity.
coral phyla? what are scleractinia?
- Phylum Cnidaria
- Scleractinia (Also called LPS – large polyp stony: hard corals)
Scleractinia? Defense mechanism?
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)
corallite?
○ corallite = skeletal unit of each polyp
in scleractinian coral
hematypic coral?
Hermatypic Corals: calcify at high rates, high [zooxanthellae]: 2 subtypes (massive & branching).
• Zooxanthellae? where do they live? what happens to them in coral when bleaching occurs?
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)
benefits of zooxananthellae to coral
• Benefits to Coral = ○ a. remove waste ○ b. provide O2 ○ c. make carbs ○ d. enhance calcification ○ e. aid lipid synthesis
benefits of coral to zoozanthellae
• Benefits to Zooxanthellae =
○ a. predator protection
○ b. access to coral nutrients
• *Controversial: No way to actually identify them (scientists constantly argue)
types of coral reproduction? gamete production?
• Coral Reproduction: hermaphroditic & separate sexes.
• - Gamete Production = - internal fertilization & release of planula (free-swimming) larvae
○ broadcast spawning
cues of reproduction for coral?
○ 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
why mass spawning?
○ 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
how can zooxanthellae be seen?
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.
confocal microscopy?
- 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
Why so many spp. In the same evening?
○ 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
larvae recruitment? why?
• 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
is recruitment successful?
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
• Local differentiation from regional natural selection or genetic drift?
○ 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
can reefs survive out of water?
• Some reef systems exposed at low tide - can still survive for hours in the temp + out of water
•
gamete production types?
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)
why can we collect coral gametes easy?
○ Gametes are positively buoyant
○ Can collect specimens as they rise to the surface
○ We can also freeze the gametes and maintain coral banks
asexual reproduction pro/con
○ Less variability but release more = lots of corals
