Lecture 8 cards

Question 1

Acropora

Answer 1

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

Question 2

Most significant environmental factors

Answer 2

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

Question 3

Temperature

Answer 3

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

Question 4

Light

Answer 4

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

Question 5

Salinity

Answer 5

Open-ocean salinity is required

Question 6

Turbidity/sedimentation

Answer 6

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

Question 7

Wave energy

Answer 7

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

Question 8

Subsidence Theory

Answer 8

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

Question 9

Glacial control theory

Answer 9

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

Question 10

Why is the productivity so high in coral reefs?

Answer 10

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

Question 11

Primary producers

Answer 11

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

Question 12

Corallite

Answer 12

Cup-shaped skeleton in 6 compartments

Question 13

Planula

Answer 13

Ciliated larva of stony corals

Question 14

Hermatypic

Answer 14

When corals have zooxanthellae. Promotes calcification.

Question 15

Acanthaster

Answer 15

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

Question 16

Mutualisms in coral reefs

Answer 16

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

Question 17

Allelochemicals

Answer 17

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

Question 18

Reefs are built by

Answer 18

Scleractinian hermatypic corals (stony corals) and crustose coralline algae

Question 19

Main causes of coral loss

Answer 19

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

Question 20

Epifauna

Answer 20

Orgs that live on the sediments

Question 21

Infauna

Answer 21

Orgs than live in the sediments

Question 22

Controlling factor of benthic orgs

Answer 22

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

Question 23

Soft sediment parameters

Answer 23

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

Question 24

Grain size

Answer 24

Indicates current velocity

Question 25

Sorting/angularity

Answer 25

Sorting is the measure of the range of particle sizes. More sorted = narrow range of particle size. Angularity = roughness

Question 26

Bioturbation

Answer 26

Sorting due to the action of organisms

Question 27

RPD

Answer 27

Redox potential discontinuity, depth below which oxidation processes are replaced by reduction processes. Measured by the property Eh, aka redox potential

Question 28

Bio factors that cause benthic organisms to be aggregated

Answer 28

Food availability and feeding activity, predation effects, reproductive effects on dispersal and settlement, behavioral effects–induced movement and aggregation