Carl Reefs

Question 1

When did corals first appear in solitary form?

When did they evolve into reef-building forms?

Answer 1

400 mya in fossil records.

25 millions years

Question 2

explain the relationship of calcium entering the ocean and corals

Answer 2

about half the calcium that enters the earth’s oceans each year is eventually bound into reefs as calcium carbonate

Question 3

explain the relationship of carbon and corals

Answer 3

This reef building system process also takes very significant loads of CO2 directly out of the marine environment (700 billion kg C /yr). this is done by binding with calcium to form calcium carbonate.

Question 4

How are coral reefs unique and complex systems?

Answer 4

• the largest structures on earth of biological origin.
• reflect thousands of years of history
• 25% of all marine life and 4-5% of all known species are found on coral reefs

Question 5

lay out the general taxonomy of corals

Answer 5

Phylum Cnidaria
Class anthozoa
Order scleractinians (largest coral order)
–> scleractinians are made up of hundreds of thousands of individual polyps.

Question 6

what are contributors of reef growth?

Answer 6

Coralline algae, sponges and other organisms combine with a number of cementation processes. They glue disconnected hard substrate together and create new substrate.
Coralline lay down the CaCO3

Question 7

In what regions is coralline algae particularly important for surf-pounded reefs?

Answer 7

The atlantic and indo-pac regions

Question 8

What conditions do coralline-driven algal ridge reefs require?
why are they important?

Answer 8

high and persistant wave action to form.
Algal ridges are one of the main structures that prevent oceanic waves from striking adjacent coastlines, helping to prevent coastal erosion.

Question 9

how is coral growth measured?

Does it show trends?

Answer 9

b/c growth is extremely slow, its measured in mm to cm per year.
Shows predictable, species, and condition-dependent patterns.

Question 10

what is the average growth rate of coral bommies? how old can they get?

Answer 10

around 12 mm per year. Can be up to 800 years of growth record.

Question 11

How does the polyp feed, what are its functions?

Answer 11

• takes in food and expels waste through its mouth
• a ring of tentacles surrounding its mouth aid in capturing food, expelling waste, and clearing away debris.
• most food is captured with the help of nematocysts.

Question 12

how does the polyp build the reef?

Answer 12

• CaCO3 secreted by polyps
• forms a protective cup, calyx, in which polyp sits.
• base of calyx is basal plate
• surrounding walls called theca

Question 13

what thin band of living tissue connect all the polyps to one another?

Answer 13

coenosarc

Question 14

how do scleractinian corals differ from other corals?

Answer 14

• they live symbiotically with zooxanthellae

- hermatypic corals

Question 15

describe zooanthellae

Answer 15

photosynthetic, single celled dinoflagellates. Live intracellularly in the endodermal tissues of stony coral polyps.

Question 16

can corals build reefs without zooxanthellae?

Answer 16

no. They produce their skeletons much slower, not nearly fast enough to build a reef.

Question 17

describe the polyp/zooxanthellae mutualism

Answer 17

• coral polyps produce CO2 and H2O as byproducts of cellular respiration
• zooxanthellae use CO2 and H2O to carry out photosynthesis
• zooxanthellae produce sugars, lipids and oxygen .
• corals use these products to grow and carry out cellular respiration

Question 18

what is the driving force behind the growth and productivity of coral reefs?

Answer 18

the tight recycling of products between polyp cells and the zooxanthellae

Question 19

why are corals best viewed as polyptrophic?

Answer 19

they use both ingested and translocated carbon as energy sources.

Question 20

what are the benefits of the mutualism for the zooxanthellae?

Answer 20

• protected from currents and grazers by the coral and nematocysts
• gain essential nutrients from the polyps (surface waters are deficient in these)

Question 21

what are the first two ways in which coral benefit from zooxanthellae?
why is this debated?

Answer 21

zooxanthellae provide oxygen to the coral and remove wast products.
corals live in relatively O2 rich, wave-washed surface waters where moving waters bring in ample O2 and wash away wast products

Question 22

what is the third way in which corals benefit from zooxanthllae?

Answer 22

zooxanthellae manufacture carbs that can be used for coral nutrition. Direct transfer of organic materials between polyp and zoox. This transfer is so great that predation/direct feeding by the corals is secondary in importance to sometimes near non-existent.

Question 23

how do elkhorn corals maximize their light-harvesting?

Answer 23

branching corals gather light from downwelling, sidewelling and upwelling light.

Question 24

what is a fourth way in which zooxanthellae are a benefit to corals?

Answer 24

enhance coral calcification and thus play a major part in the development of the support structure of corals and reefs.

• -> calcium uptake rates of Ca are directly related to light.
• by removal of CO2, zoox can shift the the carb/bicarb//CO2 interactions towards favorable conditions for CaCO3 secretions.

Question 25

what is the 5th way that zoox help out polyps

Answer 25

aid in the synthesis of lipids.
-zoox provide corals with some of the building blocks that they need to make lipids, as the incorporation of these building blocks increases with light.

Question 26

why is the synthesis that zoox aids in important?

Answer 26

zoox transfer glucose, gycerol, fatty acids, and others to their hosts, which are quickly metabolized or built into coral tissue. this also aids in making its skeleton.