Sustaining ecosystems - polar environments

arctic + antarctic

• The Arctic is an ocean surrounded by land and Antarctica is a continent surrounded by ocean

• Most of the Arctic's ice is sea ice, and this varies throughout the year 

• Melting Arctic sea ice does not raise sea levels, but Antarctica's melting land ice does cause variation in global sea volume

Arctic antarctica : location

Region within the Arctic Circle, from 66.5° to 90° north of the Equator

Landmass encompassing the South Pole and mostly south of the Antarctic Circle from 66.5° to 90° south of the Equator

Arctic antarctica : climate

Fluctuating between 10° C in summer to -40° C in winter Annual precipitation is less than 500mm per year

Colder than the Arctic with average summer temperatures of -28°C - coastal regions are warmer than the interior but winter temperatures have reached as low as -90°C (Vostok research station) Annual precipitation inland is 50mm and 200mm at the coast

arctic features

The ocean is surrounded by continents and large islands, with drifting sea pack ice that extends in winter and icebergs. Ice reaches heights of 3m in places

Mountainous regions on land, with areas covered in permanent ice and snow

Includes the treeless, permafrost, tundra region where only the surface layer of the soil thaws each summer

antarctic features

Antarctica is a continent covered by a permanent ice cap ice and surrounded by the Antarctic Ocean

Mountains up to 3794km high with the Transantarctic Mountains running across the whole continent

Ice reaches thicknesses of 4.5km in places

In winter, Antarctica almost doubles in size due to freezing seawater

Arctic antarctica : flora

Arctic region - lichen and mosses Tundra - sedges, grasses, low-growing shrubs and small flowering plants such as the Arctic poppy

Mostly lichen and some mosses Phytoplankton in the ocean

Arctic antarctica : fauna

Whales, seals, fish, wolves, caribou/reindeer, polar bears and birds such as the Snow Goose - all are specifically adapted to live in the harsh Arctic

No indigenous terrestrial mammals Penguins, seals and whales rely on the sea for their food and land provides a habitat for breeding

Arctic soil

Thin and poor quality, with very few plants Underlying rock weathers slowly due to low temperatures Permafrost sits below the active layer and remains frozen all year round The active layer melts in the summer months and ranges from 20-100cm To prevent damage to the permafrost, buildings are built on stilts

Antarctic soil + arctic tundra biodiversity, adaptations

Antarctic soils can be loose, soft, and sandy or frozen, hard, and rocky

Very little organic matter to support more than mosses or lichens

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The tundra biome has about 400 varieties of flowers but only 48 different animals

Plants in the tundra need to adapt to wet summers and dry winters:

• Summer: The top layer of soil thaws producing boggy and waterlogged land

• Winter: Frozen soil and long, dark winters

• Animals need to adapt to cold, dry, snowy conditions, as well as wet summers

fauna adaptations for polar environments

• Animal Insulation (Climate): Animals have adapted to extreme sub-zero temperatures with thick physical insulation, such as blubber in seals and double-layered fur in polar bears and musk oxen.

• Animal Camouflage (Landscape): To survive in barren, snow-covered landscapes, predators (polar bears) and prey (Arctic hares) have evolved white winter coats for camouflage.

• many animals hibernate to conserve energy

• birds migrate to other places during winter

flora adaptations for polar environments

• Plant Roots (Soil/Permafrost): (permafrost prevents further plant growth), plants cannot grow deep roots. They have adapted by growing shallow roots that spread horizontally.

• Plant Size & Shape (Climate): To survive the high winds and low moisture (less than 250mm precipitation), plants are small, round-shaped, and have tiny leaves to minimize moisture loss and avoid wind damage. They also have a rapid growing season of just 50–60 days to capitalise on the brief summer.

• e.g. caribou moss, lichens and grasses

• lots of plants become dormant to conserve energy

interdependence within polar environments : fragile marine food web

Because terrestrial plants are scarce, phytoplankton form the base of the entire food web (Phytoplankton → Krill → Fish → Penguins/Seals/Bears). Upwelling nutrient-rich ocean currents drive phytoplankton growth; if climate change alters ocean currents or melts sea ice, key hunting and breeding platforms for seals and polar bears disappear.

interdependence within polar environments : slow nutrient cycle

Sub-zero temperatures cause extremely slow decomposition, resulting in nutrient-poor soils. Plants rely heavily on herbivores (like reindeer) to fertilize soil with dung and disperse seeds on their fur.

interdependence within polar environments : permafrost feedback loop

Low-growing plants act as an insulating blanket in summer, preventing the permafrost underneath from thawing.

If human activity or warming damages surface vegetation, permafrost thaws, releasing trapped methane from litter decomp and causing surface flooding that destroys plant roots.

human effect of exploiting the polar environments

• Mineral & Oil Exploitation: oil spills pollute pristine tundra; heavy machinery melts permafrost

• Climate & Permafrost Melt: GH thaws permafrost, decomposing organic matter and releasing trapped methane, further accelerating GHG

• Species Range Shifts: Warmer temps force species to migrate further north towards the poles.

  • Apex predators like polar bears lose sea-ice platforms for hunting and face habitat loss with nowhere further north to go.

• Fragile Food Web Disruptions: Because biodiversity is extremely low, drops in key prey populations (e.g., Arctic hares) directly cause predator populations (e.g., Arctic foxes) to crash.

• human sites destroy habitats