Unique organisms
Polar sea ice is essential for the survival of many polar ecosystems.
Sea ice is frozen seawater that moves with oceanic currents, and it
provides important habitats as well as a resting place for animals.
CAFF Assessment Series No. 10: Life Linked to Ice
Due to seasonal warming, Arctic sea ice covers less area in the summer
than in the winter. Some sea ice persists year-round, creating a unique ecosystem.
The Arctic has many endemic species- meaning species that are not found anywhere else- most of which rely on
the year-round ice cover for their survival.
| Species Group: |
Present in Arctic |
% of Worldwide |
Mainly in Arctic |
Threatened |
| Terrestrial mammals: |
67 |
1% |
18 |
1 |
| Marine mammals: |
35 |
27% |
11 |
13 |
| Terrestrial and freshwater birds: |
154 |
2% |
81 |
17 |
| Marine birds: |
45 |
15% |
24 |
3 |
| Amphibians and reptiles: |
6 |
<1% |
0 |
0 |
| Freshwater and diadromous fishes: |
128 |
<1% |
19 |
|
| Marine fishes: |
250 |
<1% |
63 |
4 |
| Terrestrial and freshwater invertebrates: |
>4750 |
|
|
|
| Marine invertebrates: |
~5,000 |
|
|
|
| Vascular plants: |
2,218 |
<1% |
106 |
0 |
| Bryophytes: |
~900 |
6% |
|
|
| Terrestrial and freshwater algae: |
>1700 |
|
|
|
| Marine algae: |
>2300 |
|
|
|
| Non-lichenized fungi: |
~2030 |
4% |
<2% |
|
| Lichens: |
~1750 |
10% |
~350 |
|
| Lichenoculous fungi: |
363 |
>20% |
|
|
CAFF Arctic Biodiversity Assessment 2013: Synthesis
Fragile phytoplankton
Organisms that live within and under the sea ice tend to be small- bacteria, algae, larvae, unicellular organisms,
and different types of phytoplankton. Diatoms, a type of algae, are considered the most important primary producers
inside the sea ice. With recent Arctic sea ice levels have dropped, massive phytoplankton blooms have been occurring
in the areas. The food chains of the Arctic begin under the sea ice with these small organisms- they occupy the
lowest trophic level.
As sea ice decreases, the annual primary productivity bloom timing is shortened, leading to reduced levels of
zooplankton. As the zooplankton levels are decreased, marine life that depends on it for food will also become reduced,
causing a trophic cascade. Loss of ice will create large dispersals between the sea ice, isolate terrestrial populations,
and restrict the gene flow of marine populations. Less sea ice will also limit foraging days for polar bears,
causing tremendous decline in their populations.
