Locomotion and Feeding on the Seabed Flashcards Preview

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Flashcards in Locomotion and Feeding on the Seabed Deck (20)
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1
Q

a) Intertidal (littoral) zone

b) sublittoral zone
- Kelp forests hold on to rocks via (c)

A

a) 0-200m, transition between marine and terrestrial environments or ecotone
b) receive enough light for photosynthesis, see thriving kelp forests etc
c) holdfasts

2
Q

Ecotone

A

Transitional environment

3
Q

Benthic

A

ecological region at the very bottom of the sea

4
Q

Dysphotic zone is located on the ____ slope

A

Continental

5
Q

Where is benthic productivity at its highest?

A

underneath areas of high surface productivity

  • Mainly on continental shelves
  • Affected by surface ocean currents
6
Q

What is the abyssal plain like? (4000m and deeper)

A
  • Little known habitat – only accessible via dredge and some submersibles and ROVs
    • Little to no sunlight
    • Stable abiotic conditions (temperature, salinity, Oxygen
    relatively high, very high pressure
    • Bottom currents usually slow
    • Suit low energy lifestyles (think
    echinoderms!)
7
Q

How do abyssal zones receive nutrients?

A
  • Marine snow
  • bonanzas (whale death and sinking)
  • dead nekton sinking to the bottom
  • vertical migrations
8
Q

Form of energy production dominates in deep sea hydrothermal vents

A

Chemosynthesis

9
Q

How are species distribution influenced by substrate choice?

A
  • burrowing lifestyle can only exist in soft substrates
  • oxygen availability reduced in tightly packed substrates
  • particle size increases with increasing current size
  • living in substrates limited to soft substrates
10
Q

Describe the lifestyle of a sessile benthic animal? Given an example?

A
  • Don’t move as adults, disperse as larvae

eg. acorn barnacles (semibalamus with naupilus larvae)

11
Q

Describe the lifestyle of a slow moving species

A
  • Ciliary gliding flatworms

- Echinoderms, in Echinodomea

12
Q

Describe locomotion of Nereis, the errant Ragworm

What about when just walking?

A

Preparatory stroke:
• Anterior parapodial muscle contracts
• Longitudinal muscles on opposite side contract
• Chaetae retracted

Power stroke:
• Posterior parapodial muscle contracts
• Longitudinal muscles on same side contract
• Chaetae protracted

WALKING

  • body straight, only uses parapodial muscles
13
Q

Which species burrow ?

A

Bivalves
Polychaete lugworm
Crustaceans

14
Q

Describe how a mollusc burrows

a) function of abductor muscles
b) function of protractor muscles
c) function of retractor muscles

A

1) EXCAVATION (shell gapes and foot pushed down)
2) MOVEMENT IN (tip of foot swells by blood inflow)
3) BODY DRAWN DOWN

a) contract to free the shell
b) contract to trap blood in tip of foot like an anchor
c) contract to shorten foot to draw body down

15
Q

How do hard substrate browsers feed?

A

by grazing using radula eg. limpets

16
Q

Give an example of a direct filter feeder

A

Arenicola (Polychaete worm)

17
Q

Give an example of an indirect filter feeder

A

Terebella (Polychaete worm) using ciliated tentacle palps

18
Q

Describe the 5 different methods of suspension feeding

A

1) true sieving (RARE)
2) SPONGE flagella suspension
3) mucus sheet feeding eg. sea squirt
4) ciliary mucous feeding, eg. peacock worm
5) non-ciliary suspension feeding
6) sit and wait predators eg. bobbit worm

19
Q

give an example of a species that lives on a living substrate

A

ghost shrimp on a hydroid

20
Q

Give an example of an active forager

A

Ragworm, Nereis