Hobbies And Interests
Soil
Tundra soil is completely frozen during the winter; the upper part of the soil thaws during the brief summer. The still frozen permafrost inhibits drainage. This -- along with low air temperatures that slow evaporation -- results in summer ponds and bogs. The cycle of freezing and thawing slowly mixes the upper soil layer; it breaks rock into gradually smaller particles, causing soil formation.
Flora
The nutrients and energy that support tundra plant life are available only during the short summer. Plants battle extremely low winter temperatures -- and strong, drying winds -- by growing low to the ground. Winter grazing contributes further to stunted growth. Mosses and lichens thrive. Deep snow-cover provides protection; rooted plants growing in areas that don't get a lot of snow often have aboveground parts that die or harden before winter. Many tundra plants drop seeds on the autumn snow; the wind scatters the seeds.
Resident Mammals and Birds
Extreme cold -- and the tundra's short growing season -- regulate which animals survive year round and which ones migrate. Permanent residents have adapted by developing large bodies with short limbs, by storing body fat during the growing season and by growing dense fur or feathers that thicken in colder weather. Resident populations often fluctuate cyclically. Every three to five years certain species -- in particular the lemming and its predators -- experience population surges.
Migratory Animals and Birds
Forest dwellers -- like bears, wolves and caribou -- avoid the tundra's harsh winter by moving south to the boreal forest. Songbirds, shorebirds and waterfowl also migrate, returning to the tundra in the brief spring and summer to breed.
Insects
Mosquitoes, flies, moths, grasshoppers, blackflies and arctic bumble bees all survive in the tundra. Insects adapt to the short growing season. Certain species of moths and spiders take several years to achieve all of life's stages. A mosquito successfully overwinters in the tundra because its body fills with a chemical called glycerol; the chemical keeps it from freezing. The arctic bumblebee makes its flight muscles shiver, which raises its body temperature as much as 60 F above the outside air temperature.
Carbon Dioxide Cycle
The tundra is a carbon-dioxide sink, meaning that it makes more carbon dioxide than it gives off. Plants absorb oxygen, sunlight and water in photosynthesis during the summer, but freeze quickly when winter arrives. This phenomenon traps carbon dioxide in the permafrost, where it is stored.