Marine food webs

Question 1

What is the Secchi depth of the oceans

Answer 1

300m because they are very clear

Question 2

What is the nutrient status of the oceans

Answer 2

oligotrophic

N and Fe limited

Question 3

What are the 4 layers of the marine food web

Answer 3

Epipelagic - 0-200m most life
Mesopelagic - twilight zone
Bathypelagic - eternal darkness
Abyssopelagic - really weird organisms

Question 4

What two algal groups dominate in the oceans

Answer 4

Diatoms

Coccolithophorids - unique to oceans - need higher nutrient levels - majoy bloomers

Question 5

How does the marine microbial loop compare to the aquatic one

Answer 5

very similar except bacteria rely solely on algae for C

Question 6

Which is the only group of zooplankton in marine systems (moerozooplankton)

Answer 6

Copepods

There is no seasonality like in aquatic environments

Question 7

what is marine holoplankton

Answer 7

species that spend their entire life as plankton

e.g. krill, amphibians, jellies

Question 8

what is marine meroplankton

Answer 8

Larvae of vertebrates - do not spend entire life as plankton

Question 9

What is the significance of ice algae in the southern ocean

Answer 9

trapped in the ice over winter

invertebrates feed under melting ice in the spring

Question 10

How do southern ocean fish species protect themselves from the cold

Answer 10

some have Glyceropeptides which are anti-freeze