Coral Reefs

A ridge of jagged rock, coral, or sand just above or below the surface of the sea

Reef

Reef made out of calcium carbonate secreted by coral polyps

Coral Reef

Other organisms such as ______ ____ also create skeletons as rubble on the reef

Calcareous algae

Living part of the reef is a ___ _____ on the surface

thin veneer

Phylum and class of coral polyps

Cnidaria, anthozoans

Hexacorals are what type of coral?

Hermatypic

Octocorals are what type of coral?

Aherrmatypic

Coral polyps are micro-

carnivores

Which type of coral?
“Soft”
Don’t produce CaCO3

Dont contain zooxanthellae

Ahermtypic

Which type of coral?
“Reef-building”
Secrete CaCO3
Contains photosynthetic zooxanthellae

Hermatypic

Polyp of the coral is embedded in “_______”

Corallite

Polyps within the same colony are

clones

Corals can feed 24/7 using what approach at night?

Carnivorous

What are the four feeding strategies of corals?

Feed on particles
Zooxanthellae Symbiosis
Mucus
Mesenterial filaments

Algae living symbiotically in the tissues of another organism

Zooxanthellae

The zooxanthellae found inside of corals are also called

dinoflagellates

The two life stages of zooxanthellae:

Free-living with a flagella
Inside of coral tissue

What does the coral provide for the dinoflagellates

CO2, H2O, nutrients
Stable location in sunlight
UV protection

What does the zooxanthellae do for the coral?

Fixes CO2 and provides carbohydrate fuel

Coral-zooxanthellae symbiosis is an example of what?

Efficient nutrient cycling

Corals excrete mucus on their surface for what purpose?

Sediment removal
Feeding by other animals

Coil tubes attached to the gut wall. Excrete digestive enzymes for feeding and defense

Mesenterial filaments

Corals growing too close together will use what to “take out” their neighbor?

mesenterial filaments

Coral growth is generally

slow and upwards

Coral colonies can live for how long

decades to centuries

Largest coral reef is

GBR, australia

How are corals similar to trees in growth?

Annual growth rings that count age

What inside of coral growth rings can inform about past climate conditions?

chemical signatures

What sex can a coral organism be?

Male, Female, or both

Asexual reproduction is is important for

Increasing colony size
Budding
Fragmentation

Storm or disturbance breaks part of a colony, so asexual reprod. is used to form a new colony

fragmentation

Sexual reproduction is important for

Inc genetic diversity
Starting new colonies

Sexual reproduction is _______ across colonies to maximize success and diversity

Synchronized

Sexual reproduction occurs once per year, usually when

currents are in favor of forming new colonies

Coral morphology varies with

Location in reef
Environmental conditions

The four types of coral morphologies

Branched
Massive
Foliose
Tabular/Plate

A coral in a high water flow env. will have what kind of morphology?

Massive

A coral in a low water flow env. will have what kind of morphology?

More branched and skinny

Shallow reefs mainly contain which kind of coral (herma/aherma)

hermatypic

deep reefs contain what kind of corals (herma/aherma)

both

The corals in deep reefs are more tolerant to

lower temperatures

What are the five main REEF morphologies?

Fringing
Patch
Barrier
Submerged shelf-edge
Atoll

Reef that runs directly parallel to the shore, very close inland

Fringing reef

Reefs within a lagoon between the land and the barrier reef

Patch reefs

Wider reef with a lagoon between it and the land mass

Barrier reef

Reef submerged under water and formed on the edge of the shelf

Submerged shelf-edge reef

Ring-like reef with no land in the middle, longest to develop

Atoll

Four main reef zonations?

Back reef
Reef crest
Fore reef
Deep reef

Spur & groove pattern of the reef forms in what part of the reef?

Reef front

How are reefs able to develop in much deeper, cooler water in the drop-off zone of the reef?

Upwelling
Flat morphology

What kinds of species are found at the reef crest? (high stress)

Lots of smaller corals

What kinds of species are found at the reef front (lower stress)

Larger branching and massive corals

What kinds of species are found in the deep reef? (Low light)

Flat corals

What kinds of species are found in patch reefs? (good light, medium wave action)

Mixture of all species

Reef primary production is _____ gC/m2/y

3000

Primary producers are “_______”: Not obvious which is responsible for PP in what proportions

Cryptic

Main kinds of PPs in the reef?

Zooxanthellae
Algal turf
Coralline algae
Seagrasses, macroalgae, benthic diatoms

The reef food web is mainly ___-based

grazin

The main grazers on the reef are

PARROTFISH
sea urchins

Only __% of PP ends up in the detritus pool

5%

The reef food web has tight ____ ____

nutrient recycling

Coral bleached for too long ends up covered in ___ ____, a complete change in habitat

algal turf

The 2 biggest threats to coral reefs is

temperature increases and El Nino

Outbreaks of what species are really bad for corals (they eat them)

Crown of thorns starfish

Other factors leading to the decline of coral reefs:

Runoff → algae → less light
Disease
Overfishing of predators of coral-eaters
Decreasing pH

Why is decreasing pH a problem?

Skeleton dissolves and polyp is exposed to be eaten