Zooplankton, Deep Sea Nekton

Question 1

What are zooplanktons three mechanisms of buoyancy?

Answer 1

1. Body size: small size increases S:V ratio and friction with water column
2. Appendages and projections: help with S:V
3. Density: high lipid content, air bladders

Question 2

Mesoplankton

Answer 2

Zooplankton (e.g. copepods)

0.2-20 mm

Question 3

What type of zooplankton are the eggs considered?

Answer 3

Microplankton and mesoplankton

Question 4

Macroplankton

Answer 4

Zooplankton

2-20cm

Question 5

Megaplankton

Answer 5

Zooplankton

20cm-2m

Question 6

What are the three groups of zooplankton?

Answer 6

1. Mesoplankton (0.2-20mm)
2. Macroplankton (2-20cm)
3. Megaplankton (20cm-2m

Question 7

Neuston

Answer 7

Planktonic organisms living at the sea surface

- Includes all size zooplankton and phytoplankton

Question 8

Pleuston

Answer 8

A type of neuston that includes plankton forms that break the surface and use wind for dispersal

Question 9

Meroplankton

Answer 9

Organisms with a life stage in the plankton and another in the benthos

Question 10

Holoplankton

Answer 10

Organisms with a full cycle in the water column

Question 11

Dynamics of movement on fluid

Answer 11

1. Streamlining and body shape: Reduces water resistance
2. Reynolds number (Re): The ratio or coefficient of drag
3. Countershading and Color
4. Nekton Diversity

Question 12

Body shapes of fish

Answer 12

Fusiform: shaped for fast, long swimming (tuna, sharks)

Laterally compressed: shaped to make tight, close turns (rock fish)

Eel-like: shaped to live in between sea grass, rock

Depression or Flat: shaped to rest or hide in the bottom (flounders)

Question 13

Objects with a high Re…

Answer 13

Dynamics driven by objects large size and speed

- object continues to move because they have a momentum

Question 14

Objects with a low Re…

Answer 14

Dynamics driven by water viscosity

- After source of movement stops, object stops

Question 15

Countershading

Answer 15

dark on top, light on bottom

- Most basic camouflage

Question 16

Nekton diversity

Answer 16

• Invertebrates and reptiles
• Fish
• Deep sea fish
• Marine mammals
• Seabirds
• Fisheries

Question 17

Two groups of fish

Answer 17

bony

cartilaginous (sharks and skates)

Question 18

Characteristics of cartilaginous fish

Answer 18

• Placoid scales
• Heterocercal tail
• Exposed gill slits
• Large pectoral fins

Question 19

Characteristics of bony fish

Answer 19

• Cycloid scales
• Homocercal tail
• Operculum present
• Small pectoral fins
• Jaw morphology

Question 20

Four relevant families of bony fish

Answer 20

1. Scrombridae (mackerel, tuna)
2. Salmonidae (salmon and trouts)
3. Pleuronectiforms (flatfish)
4. Gadidae (cod and hake)

Question 21

Characteristics of the fish family: Scrombridae

Answer 21

• Most schooling fish in surface waters
• Migration

E.g. mackerel

Question 22

Characteristics of the fish family Salmonidae

Answer 22

• Marine and freshwater species
• Migratory but native to North hemisphere
• Carnivorous

E.g. salmon

Question 23

Characteristics of the fish family Pleuronectiforms

Answer 23

• Asymmetrical as adults, flattened body
• All marine

E.g. flounders

Question 24

Characteristics of the fish family Gadidae

Answer 24

• Marine
• Slow growing
• Long life span

E.g. cod

Question 25

Collapse of cod stocks

Answer 25

Allowed the build up of shrimp and crab

Question 26

Fishing down the trophic web

Answer 26

Overfishing; as top predators are removed from fishing, smaller fish lower in the web are targeted, reducing their numbers

Question 27

zones of the deep sea

Answer 27

Meso, bathy, Abyssopelagic

Question 28

How does the habitat of the deep sea compare to the epipelagic zone?

Answer 28

- 10 times less abundant - lack of primary production - darker, colder, higher pressure

Question 29

Mesopelagic zone

Answer 29

- Some twilling light but no photosynthesis - Zone where permanent thermocline occurs - Zone where the OML (oxygen minimum layer) occurs

Question 30

Where does the mesopelagic zone get its oxygen from?

Answer 30

- Atmosphere exchange - Photosyntheis - Ocean conveyor belt

Question 31

Why is there a small increase in oxygen below the OML? (Oxygen minimum layer)

Answer 31

Lack of nutrients

Question 32

4 adaptations of the mesopelagic

Answer 32

1. Bioluminescence and photophores: photophores located on ventral side; bioluminescent cells 2. Sensory organs: Large, highly sensitive eyes 3. 'Hungry' anatomy: Specialized feeding anatomy 4. Vertical migration ability

Question 33

Conditions of the Abyssopelagic

Answer 33

- Always dark - Always cold (1-2 degrees Celsius) - Under higher pressure

Question 34

Adaptations to the Abyssopelagic

Answer 34

No need for swim bladders, streamlining, colors, large eyes