This enormous biome, extremely uniform in appearance, covers a fifth of the earths surface.
GENERAL CHARACTERISTICS*Extremely cold climate* Low biotic diversity* Simple vegetation structure* Short season of growth and reproduction* Energy and nutrients in the form of deadorganic material
Sun’s oblique angle – receive little solar energy Low Temperatures – 29 degrees celsius to 7 degrees celsius (winter) and not more than 10 degrees celsius (summer) Short summer days – 6 to 10 weeks. sun shines almost 24 hours a day. Long winter – 9 months. almost 24 hours night
Poor soil – reduced decomposition due to cold climate Strong winds Cold and dry climate – precipitation 6 to 10 inches of rain per year latitude – Arctic tundra or Alpine tundra Permafrost – layer of permanently frozen subsoil (600 meters deep)
ARCTIC TUNDRA Arctic tundra is found almost entirely in the Northern Hemisphere. In the southern hemisphere it is found on isolated islands off the coast of Antarctica as well as the Antarctic peninsula. It can also be found in Northern portions of Canada, Alaska, Greenland, and the United States
ARCTIC TUNDRA higher latitude Short growing season – 50 to 60 days permafrost vegetation – protects the permafrost through shading and insulation Freezing and thawing of the upper layer of soil – unique, symmetrically patterned landforms. Action of frost Cryoplanation – molding of the landscape by frost action
SOLIFLUCTION TERRACES Mass movement of supersaturated soil over the permafrost
ALPINE TUNDRA Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. It is not found in distinct areas as the arctic tundra. Alpine tundra is scattered in many regions all around the world.
ALPINE TUNDRA permafrost – high elevations little Short growing season – 160-180 days soils are drier – only alpine wet meadows and bogs have similar soil moisture as the Arctic tundra precipitation (snowfall and humidity) – higher but steep topography induces a rapid water runoff
NUTRIENT CYCLING IN THE TUNDRA
LowTemperatures and Extreme Seasonality Control Tundra Productivity and Nutrient Cycling
Primary production on the tundra is low, a consequence of low temperature and a short growing season ranging from 50-60 days in the high Arctic to 160 days in the low-latitude alpine tundra. These physical constraints result in a low availability of nutrients that further function to reduce productivity
Dead organic matter functions as the nutrient pool, but most of it is not directly available to plants. Because the tundra soil does not store available nutrients in any great quantity, plants depend on the release of nutrients for decomposition, the uptake of which is often aided by mycorrhizae
Leaching or removal of nutrients is minimal, occurring mostly at the beginning of the growing season. Melting snow releases nutrients frozen over winter in the litter, excreta of animals, and microbes.
A rapid upward movement of nutrients early in the season at the expense of below-ground biomass supports fast shoot growth. * Sixweeks into the growing season, plants start to send nutrients below-ground. As the cold approaches, the above ground tissues die, and their dead parts add to the accumulation of organic matter. Nutrients leached from the dead leaves are accumulated by mosses or are frozen into place until the following summer’s snowmelt
Plant AdaptationsGrowing close together andlow to the ground are someof the adaptations that plantsuse to survive. This growingpattern helps the plant resistthe effects of coldtemperatures and reduce thedamage caused by theimpact of tiny particles of iceand snow that are driven bythe dry winds
Only plants with shallow root systems grow in the Arctic tundra because the permafrost prevents plants from sending their roots down past the active layer of soil. Plants also have adapted to the Arctic tundra by developing the ability to grow under a layer of snow Plants lose water through their leaf surface. By producing small leaves the plant is more able to retain the moisture it has stored.
CARIBOU MOSS Although it is called caribou moss, it is actually a lichen. Lichens are two separate organisms. They are made up of fungi and algae, which live and grow together. The spongy threads of lichens support and protects the algae. The tissues of lichens arent easily damaged by frost. .
LABRADOR TEA It will grow up straight in the southern latitudes of the tundra, but in the colder northern latitudes it will creep over the ground forming a carpet. PASQUE FLOWER
Because of the cold wind, most plants are small perennial groundcover plants which grow and reproduce slowly. They protect themselves from the cold and wind by hugging the ground. Taller plants or trees would soon get blown over and freeze. When plants die they dont decompose very quickly because of the cold. This makes for poor soil conditions.
Many flowering plants of the alpine tundra have dense hairs on stems and leaves to provide wind protection or red-colored pigments capable of converting the suns light rays into heat. Some plants take two or more years to form flower buds, which survive the winter below the surface and then open and produce fruit with seeds in the few weeks of summer.
WHAT DOES THE SNOW DO TO HELP THEPLANTS? Snow beds are found where large amounts of snow accumulate– this provides a continuous supply of water throughout the growing season Snow patch communities occur where wind driven snow accumulate in shallow beds– this layer of snow protects the plant beneath. Although, the plants have a shorter growing season.
FAUNALow in DiversityTundra animals are well Adapted to the Cold
POLAR BEAR Polar Bears do not enter true hibernation in the winter as this is a period of hunting, however, some Polar Bears and pregnant females in particular will enter a deep sleep where their heart rates will drop. They have two layers of fur which is so warm that adult bears can easily overheat when they run. Most of the suns rays reach their black skin, which absorbs the heat and keeps the polar bear warm.
Their teeth and claws are very sharp so they can catch their prey easily (seal). Also, their claws aid them in digging out the snow in making snow den’s for the women to give birth
Repeated freezing and thawing can destroy living tissue. The Alaska blackfish overcomes this problem by producing chemicals within its body that lowers the freezing temperature of cell fluids. Much like the antifreeze we add to the water in our vehicles, the "antifreeze" of the Alaska blackfish prevents the formation of large ice crystals within its cells, even at low temperatures. The Alaska blackfish can survive temperatures of-20 degrees C (4 F) and the complete freezing of some body parts, including their heads, for up to several days.
ARCTIC FOX The Arctic fox has adapted to its environment by growing long fur that changes color with the season for camouflage. Its legs, ears, and muzzle are short to conserve heat, and uses its tail like a muffler when cold.
CARIBOU The caribou lives in the arctic tundra, Their large, spreading hooves support the animal in snow in the winter and marshy tundra in the summer. Caribou are also great swimmers and use their feet as paddles. They can also lower their metabolic rate and go into a semi-hibernation when conditions get very harsh. Caribou have special microorganisms in their stomachs which let them digest lichen.
ERMINE- SHORT-TAILED WEASEL Their ermine paws have claws which enables it to dig. The front feet are smaller than the back which helps it fit into small, tight spaces. The coat of the ermine changes with the seasons and camouflages it from predators. In winter the ermines coat is white blending in with the snowy environment. In warmer seasons the fur turns brown again matching the color of the landscape.
SOME COMMON ADAPTATIONS OF RESIDENTANIMALS IN THE ARCTIC AND ALPINE TUNDRA: - short and stocky arms and legs. - thick, insulating cover of feathers or fur. - color changing feathers or fur: brown in summer, and white in winter. - thick fat layer gained quickly during spring in order to have continual energy and warmth during winter months. - many tundra animals have adapted especially to prevent their bodily fluids from freezing solid. - resident animals like the ptarmigan and the ground squirrel use solar heating to stay warm and save energy. Both animals stay out in the sun to warm up and during the summer when the weather is warm, seek shade to cool off.
HUMAN IMPACT ON TUNDRA BIOME
OVERHUNTING The overhunting of endangered species in the early 1900s resulted in the eradication of animals such as the musk oxen in the Alaskan tundra, which sailors coveted for the food and clothing it offered. Eventually, governments began to recognize the issue and responded by enacting laws to protect the tundra animals. Because of this, musk oxen and caribou numbers are slowly rising again in places such as Canada where they were once close to extinction.
SABER-TOOTHED TIGER Smilodon became extinct at the end of the Pleistocene around 10,000 BC, a time which saw the extinction of many other large herbivorous and carnivorous mammals. Prehistoric humans, who reached North America at the same time and are known to have hunted many of the species that disappeared, are often viewed as responsible for this extinction wave.
POLLUTION AND GLOBAL WARMING Global warming will continue to have an inevitable effect on the tundra, the worlds most fragile biome. Rising temperatures will melt glaciers and permafrost, flood the surrounding areas and kill the delicate plant species.
Polar bears are in danger of extinction due to the climate change that is melting their habitat. Their main prey is seals, who live on the ice; the less ice there is, the fewer seals there are for the polar bears to eat.
Climate change and hunting haveWOOLLY MAMMOTH long been blamed for forcing the mammoth into decline at the end of the Pleistocene era about 10,000 years ago. Researchers estimate that the last mammoth died out 4,000 years ago.
OIL DRILLING The Arctic holds the worlds largest remaining untapped gas reserves and some of its largest undeveloped oil reserves. A significant proportion of these reserves lie offshore, in the Arctics shallow and biologically productive shelf seas. According to the oil industry, the Arctic is the final frontier for petroleum development.
Oil drilling pollutes the water, land and air surrounding the tundra. Russias nickel mines serve as a vivid example of the effect that oil drilling can have on the habitat. Many plants and animals have either been killed or have permanently fled the area after the area became contaminated by the harmful gases and materials released during drilling.
On January 3, 1959, Alaska gained statehood along with its natural resources. Rich oil deposits was one of the many natural resources found in this vast area causing a new breed of fortune hunters to come to Alaska. On March 24th, 1989, millions of gallons of oil spilled into the ocean when Exxon Valdez (an oil tanker) crashed into a reef. This spill affected all of the wildlife greatly, tens of thousands of seabirds, salmon, herring, and halibut were killed from a disaster that wouldnt have happened except for the intervention of man. An estimate was made that 100,000 birds died in the oil spill, something that could have been avoided. Even though the bulk of the oil was finally cleaned up, some of it still lingers there.
OVERDEVELOPMENT Building roads and structures in the tundra has attracted much more human traffic to an area where merely stepping on the fragile plant species can kill them. Without plants to contain the soil, the earth quickly erodes and threatens to destroy the entire biome.
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.