Study Guide for Module 12

Question 1

Benthos

Answer 1

Marine organisms that live on the sea bottom

Question 2

Nekton

Answer 2

Marine organisms that swim strongly enough to move against the ocean current

Question 3

Plankton

Answer 3

Marine organisms that cannot swim strongly enough to move against the ocean current

Question 4

Meiofauna

Answer 4

Microscopic invertebrates living within the interstitial spaces of aquatic soil

Question 5

Sand dollar

Answer 5

Benthos

Question 6

Larval fish

Answer 6

Plankton

Question 7

Shark

Answer 7

Nekton

Question 8

Jellyfish

Answer 8

Plankton

Question 9

Crab

Answer 9

Benthos

Question 10

Why is the continental shelf also called “subtidal”?

Answer 10

It stays underwater regardless of the tides

Question 11

How does wave action determine the types of substrate particles present in a shelf environment?

Answer 11

Heavey wave action washes away fine particles and leaves mainly sand. Areas without much wave action, or those protected from it, have fine sediments

Question 12

What are the 3 types of organisms that make up benthos?

Answer 12

Infauanal organisms, epifaunal organisms, meiofaunal organisms

Question 13

Which type of soft substrate contains little oxygen and lots of organic matter?

Answer 13

A muddy bottom substrate

Question 14

Which type of community has a larger number of species living in it: a soft-bottom estuary or a soft bottom shelf community?

Answer 14

Soft-bottom self communities

Question 15

Are the infauna evenly distributed throughout the substrate in a soft-bottom subtidal community?

Answer 15

The infauna are not evenly spaced in the substrate of soft-bottom salt communities

Question 16

What is the major food source of the unvegetated soft-bottom self communities?

Answer 16

Detritus

Question 17

What does scuba stand for?

Answer 17

Self-contained underwater breathing apparatus

Question 18

You are studying a shelf community with a snandy-bottom substrate. What type of feeding mechanism would you expect most of the organisms living there to use?

Answer 18

Most organisms in a sandy bottom shelf community will use suspension feeding

Question 19

What makes meiofauna different from the infauna in a substrate?

Answer 19

Meiofauna are small enough to fit between the individual particles of the substrate

Question 20

A student tells you he observed a soft-bottom community in which suspension feeders and deposit feeders were roughly equal in number and lived in close proximity to one another. Why should you be skeptical of this student’s report?

Answer 20

Suspension feeders do not live near deposit feeders because deposit feeders churn through the sediment looking for food. It’s also rare to find them in equal numbers

Question 21

What kind of seagrass do you typically find in the tropics? What kind do you typically find in temperature regions?

Answer 21

In the tropics, turtle grass is most commonly found, while in temperature areas eelgrass is more common

Question 22

Seagrasses do not provide much live plant food to organisms living in the community. How does their tremendous primary productivity get into the food chain, and what other benefits do they provide for their community?

Answer 22

Many organisms feed on the decaying seagrasses, Seagrasses roots aid in keeping soft substrate more stable, seagrass blades provide shelter for many creatures, and the blades are locations on which algae and organisms directly dwell

Question 23

Name at least 2 organisms that feed directly on live seagrasses

Answer 23

Manatees, nudibranchs, sea urchins, sea turtles, and a few species of bird, like Canadian geese

Question 24

What type of organisms dominates the hard bottom shelf communities: infauna or epifauna? Why?

Answer 24

Epifauna, this is because there is little soft substrate into which infauna can bury

Question 25

Why are seaweeds so common in hard-bottom shelf communities and not in soft-bottom shelf communities?

Answer 25

Seaweeds need a hard surface onto which they can hold because they do not have roots that can anchor them to a soft substrate

Question 26

What factors keep most animals from grazing on seaweed?

Answer 26

Having special chemicals that give them a bad flavor, some are leather-like, and others incorporate calcium carbonate into their tissues to give them a hard-shelled outer surface

Question 27

What are some of the environmental requirements necessary for kelp growth?

Answer 27

Sunlight; a hard substrate on which to attach; and cold, nutrient-rich water in order to grow

Question 28

What is the difference between a kelp bed and a kelp forest?

Answer 28

A Kelp bed has kelp that is not tall enough to reach the surface of the water. While kelp forest is composed of kelp that grows all the way to the surface forming a canopy of the surface

Question 29

Which has more chromosomes, the cells of the gametophyte generation of kelp or the cells of the sporophyte generation of kelp?

Answer 29

The cells of the sporophyte generations

Question 30

A professor tells you that you are looking at full-grown giant kelp. However, you are looking at it with a microscope, and you can see the entire organism. How can the professor be correct?

Answer 30

You are looking at an individual from the gametophyte generation of giant kelp

Question 31

Brittle Starfish

Answer 31

Holdfasts and kelp

Question 32

Octopuses

Answer 32

Substrate between kelp

Question 33

Fishes

Answer 33

Up in the water column on the blades of kelp

Question 34

Small sessile suspension feeders

Answer 34

Directly on the kelp strips and blades

Question 35

Explain why, during a sea urchin explosion, kelp plants are so easily killed off yet are rarely completely eaten

Answer 35

During a sea-urchin population explosion, there is not enough drift kelp on which to feed. So sea urchins crawl along the bottom and eat holdfasts of the kelp

Question 36

What are benthos organisms? Give an example

Answer 36

Benthos - marine organisms that live on the sea bottom (star fish, sea urchin)

Question 37

What are Nekton organisms? Give an example

Answer 37

Nekton - Marine organisms that swim strongly enough to move against the ocean current (Tuna)

Question 38

What are Plankton organisms? Give an example

Answer 38

Plankton - Marine organisms that cannot swim strongly enough to move against the ocean current (planula larvae, jellyfish)

Question 39

What determines the size of the particle in the substrate of a shelf community?

Answer 39

Wave action

Question 40

What is meiofauna?

Answer 40

Meiofauna are microscopic organisms that live between the sediment particles

Question 41

What is infauna?

Answer 41

Infauna are organisms that burrow into the substrate

Question 42

What is epifauna?

Answer 42

Epifauna are organisms that live on top of the substrate

Question 43

What type of infauna live in sandy substrates

Answer 43

Filter feeders

Question 44

What types of infauna live in muddy substrates?

Answer 44

Deposit feeders

Question 45

Why do deposit feeders and filter feeders generally not live together?

Answer 45

Deposit feeders stir up the sediment which can clog the filter of filter feeders

Question 46

What provides the primary productivity of the vegetated soft-bottom community?

Answer 46

Seagrasses

Question 47

What are all the methods that the kelp plant has at its disposal to avoid getting eaten

Answer 47

- Thick leathery leaves - A chemical that makes them taste bad - Some incorporate calcium carbonate into their tissues that give them a hard shell surface

Question 48

What are 3 conditions necessary for kelp growth?

Answer 48

- Coldwater, nutrient-rich water - Hard substrate - Sunlight

Question 49

How does a kelp bed become a kelp forest?

Answer 49

The kelp will grow long enough to reach the surface and float, creating a canopy in the way that a rain forest does

Question 50

Sea urchins prefer to eat the floating kelp blades that have come loose from the kelp. If they are not able to find that, what else will they eat?

Answer 50

As they crawl along the bottom they will encounter the holdfast of other kelp and will eat that