The
tundra is one of Earth's three major carbon dioxide sinks. A carbon
dioxide sink is a biomass which takes in more carbon dioxide than it
releases. Carbon dioxide is a greenhouse gas that contributes to global
warming. During the short summer tundra's plants take in carbon dioxide,
sunlight and water in the process of photosynthesis. Plants normally
give off carbon dioxide after they die and decompose. But because of
the short, cool summer and freezing winter temperatures, plants can't
decompose. Remains of plants thousands of years old have been found
in the tundra permafrost. In this way the tundra traps the carbon dioxide
and removes it from the atmosphere. Today global warming is melting
the permafrost of the tundra and every year several feet of tundra are
lost. As the tundra melts, the plant mass decomposes and returns carbon
dioxide to the atmosphere.
The tundra is a very fragile environment. The
extremely cold temperatures makes it a difficult environment to survive
in during the winter, and plants and animals have a hard time coping
with any extra stresses and disturbances. More people moving to the
tundra to work in the mines and oil rigs have created towns and more
roads. Some animal's movements to traditional feeding and denning grounds
have been disrupted by these obstacles. When they try to pass through
a town they are often scared away or shot. With their feeding patterns
disrupted, many polar bears have starved. The Alaskan oil pipeline was
built across a caribou migration route. In some places the pipeline
has been raised above the ground so the caribou can pass under it. Pesticides
have been used to control the hordes of insects. Thousands of migrating
birds come to the tundra because of the abundant insects. Through the
food chain the pesticides reach many of the animals that live on the
tundra.
Pollution from mining and drilling for oil
has polluted the air, lakes and rivers. The land around some nickel
mines in Russia has become so polluted that the plants in the surrounding
area have died. Footprints and tire tracks can be visible for many years
after they were made. When the sun hits the ruts it causes the permafrost
to melt. This causes erosion and the ruts get bigger, and eventually
the ruts turn into gullies. Tracks made during WW II have grown so large
that some of them are now lakes.
The tundra is not a cold and useless wasteland.
It is a very fragile environment and the plants and animals that have
made their home on the tundra biome have made some incredible adaptations
to the long, cold winters and the short but abundant summers. They live
on a precarious edge and the smallest stresses can bring about their
destruction.
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