Ecological consequences of sea ice decline Flashcards Preview

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Flashcards in Ecological consequences of sea ice decline Deck (12)
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1
Q

What is the cryosphere?

A

The cryosphere is the frozen water part of the Earth system

2
Q

Difference between Antarctic and Arctic

A

Antarctica:
Land mass surrounded by ocean- can move freely = high drift speeds, tends to be covered in snow.

Arctic:
Semi-enclosed ocean almost completely surrounded by land, low snowfall

3
Q

Loss of summer sea ice has accelerated in the past four decades
When will arctic be ice free?

A

At the current rate of 12% per decade, Arctic will be 95% ice-free by 2100.

4
Q

Sea ice extent has declined dramatically during the 20th century in both hemispheres.
Where has the trend been more obvious?

A

The Arctic

5
Q

Impacts of sea ice decline on fauna?

A

Pagophilic species (dependent on ice)
Sea ice as a feeding ground
Sea ice as a substitute to land for reproduction

6
Q

Ecological consequences of sea ice decline

A

1) Alteration of food web
2) Habitat loss
3) Extinctions?

7
Q

Sea ice decline and alteration of food web

Simplified trophic levels

A

Photosynthetic algae, sea ice algae and phytoplankton
Zooplankton (krill)
Ice-associated vertebrates

8
Q

Other than phytoplankton, what acts as a key part of the Arctic food web?

A

Polar cod

9
Q

Cascade effect through the food chain

A

Decrease in the extent and duration of ice cover

Perturbations of the food web at different levels

Bottom-up impact: perturbations work their way up through the food chains

10
Q

Earlier retreat of sea ice and reduction of sea ice cover equals decline in ice algae production which means…

A

Shortening of the time for growth and reproduction
Greater exposure to predators
Food shortage

11
Q

What will sea ice decline mean for walruses?

A

Females feed on benthic prey in shallow waters when nursing their young
Sea ice provides walruses with a resting platform, access to offshore feeding areas

12
Q

Are emperor penguin (Aptenodytes forsteri) facing extinction ?

A

The emperor penguin life cycle depends on sea ice.
Low sea ice concentration reduces adult survival through its effect on the food web (low food resources and/or high pre- dation)