Zooplankton

Question 1

What happens to the population if cellular growth rate > mortality rate?

Answer 1

The population will increase

Question 2

What happens to the population if mortality rate > cellular growth rate?

Answer 2

The population will decrease

Question 3

What are zooplankton?

Answer 3

Microscopic marine animals which cannot control their horizontal position in the water column

Question 4

Do zooplankton mostly eat phytoplankton or other zooplankton?

Answer 4

Other zooplankton

Question 5

What are some examples of zooplankton?

Answer 5

• Krill
• Copepods
• Mesozooplankton
• Protozoan grazers (ex: nanoflagellates)
• Jellyfish

Question 6

How does sea ice form the perfect phytoplankton habitat?

Answer 6

• Constant source of light
• Excess nutrients from freshwater
• Protection from predators

Question 7

Swarming is a behavior that attracts large predators. Why do zooplankton (krill) swarm?

Answer 7

• 10:1 rule!
• The natural predators of krill (fish) are much smaller than a whale
• This behavior would be effective against a fish
  There are more small predators than large predators in the ocean…swarming events are rare

Question 8

How do copepods support fisheries?

Answer 8

Transfer primary production up through the food web up to larger animals

Question 9

What will zooplankton abundance typically follow?

Answer 9

The spring bloom

Question 10

What is the match/mismatch hypothesis?

Answer 10

The idea that you can predict how well a fishery will do based on if fish spawning is in alignment with the Spring bloom

Question 11

Why are microzooplakton important to marine food webs?

Answer 11

They make pico plankton energy available to upper trophic levels

Question 12

What is a trophic cascade?

Answer 12

A change in one trophic level results in a “trickle down” effect on the trophic levels below it
(ex: sea otters and kelp Forrests)

Question 13

What can anthropogenic activities do to jellyfish populations?

Answer 13

Anthropogenic activities can select for conditions that favor certain kinds of jellyfish
Ex:
Eutrophication —> phytoplankton bloom = more turbidity (jellyfish do not need to see) —> more CO2 in ecosystem
—> hypoxia (jellyfish can tolerate no O2, fish cannot)

Question 14

Why are jellyfish taking over coastal ecosystems?

Answer 14

• Global warming: warm waters = earlier emergence
• Overfishing: zooplanktivorous fish = overfished = more food for jellyfish
• Eutrophication
• Trans oceanic shipping: ballast water transport

Question 15

What are the consequences of too many jellyfish within an ecosystem?

Answer 15

Ecosystem production is shunted to jellyfish instead of fish

Question 16

How might global warming during winter affect zooplankton populations and the spring bloom

Answer 16

• Warm winter = less intense spring bloom (less plankton)
• Cold winter = more intense spring bloom (more plankton)
  -Zooplankton will decrease unless, there are other factors that are favorable (ex: warm temperature)