Lecture 8 cards Flashcards

1
Q

Acropora

A

Species of coral–150 spp in pacific, 3 spp in atlantic

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2
Q

Most significant environmental factors

A

Temperature, light, salinity, turbidity/sedimentation, wave energy

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3
Q

Temperature

A

About 20C, max range 18-40C, cold upwellings prevent health, cooler water favors algal growth rather than coral growth, so competition could be what prevents coral success

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4
Q

Light

A

Photosynthesis is essential for dinoflagellates (zooxanthellae) that are essential for rapid calcification. Compensation depth for coral growth 15-20% of surface light intensity

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5
Q

Salinity

A

Open-ocean salinity is required

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6
Q

Turbidity/sedimentation

A

Can inhibit coral growth, decreased light attenuation decreases photosynthesis, sediments can foul the surfaces and smother animals, some animals produce mucus sheets in response

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7
Q

Wave energy

A

Corals strive with strong water movements. Prevents sedimentation, high oxygen content, skeletons resistant to shock, cannot withstand aerial exposure

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8
Q

Subsidence Theory

A

Corals fringing land masses or volcanoes are the result of crust subsiding, allowing reefs to grow upward and outward. Making 3 stages of reef development fringing-barrier-atoll

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9
Q

Glacial control theory

A

Change in sea level caused by formation and melting of glaciers allowed corals to grow into very high structures

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10
Q

Why is the productivity so high in coral reefs?

A

Favorable light conditions, high temperatures, constant water movements to replenish nutrients and enhance diffusion rates, tight recycling of nutrients

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11
Q

Primary producers

A

Dinoflagellates (zooxanthellae, 70% of tissue weight of corals), filamentous/encrusting algal mats, calcareous algae (reds, greens), N-fixing cyanobacteria, phytoplankton

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12
Q

Corallite

A

Cup-shaped skeleton in 6 compartments

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13
Q

Planula

A

Ciliated larva of stony corals

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14
Q

Hermatypic

A

When corals have zooxanthellae. Promotes calcification.

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15
Q

Acanthaster

A

Crown-of-thorns echinoderms, attack coral reefs, outbreaks occur in cycles possibly by removal of top predator or by weather

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16
Q

Mutualisms in coral reefs

A

Zooxanthellae in many reef organisms, cleaning relationships, burrowing shrimp and gobiid fish, clown fish and anemones

17
Q

Allelochemicals

A

Toxic chemicals that can harm or prevent the growth of other coral species

18
Q

Reefs are built by

A

Scleractinian hermatypic corals (stony corals) and crustose coralline algae

19
Q

Main causes of coral loss

A

Predatory starfish, infectious diseases, destructive fishing techniques, poor land use practices, coral bleaching

20
Q

Epifauna

A

Orgs that live on the sediments

21
Q

Infauna

A

Orgs than live in the sediments

22
Q

Controlling factor of benthic orgs

A

Substratum type–hard vs. soft, rocks, skeletons, wood, etc

23
Q

Soft sediment parameters

A

Grain size, sorting/angularity, vertical distribution of sediment properties

24
Q

Grain size

A

Indicates current velocity

25
Sorting/angularity
Sorting is the measure of the range of particle sizes. More sorted = narrow range of particle size. Angularity = roughness
26
Bioturbation
Sorting due to the action of organisms
27
RPD
Redox potential discontinuity, depth below which oxidation processes are replaced by reduction processes. Measured by the property Eh, aka redox potential
28
Bio factors that cause benthic organisms to be aggregated
Food availability and feeding activity, predation effects, reproductive effects on dispersal and settlement, behavioral effects--induced movement and aggregation