http://www.blueplanetbiomes.org/world_biomes.htm

What is a Biome?

A biome is a large geographical area of distinctive plant and animal groups, which are adapted to that particular environment. The climate and geography of a region determines what type of biome can exist in that region. Major biomes include deserts, forests, grasslands, tundra, and several types of aquatic environments. Each biome consists of many ecosystems whose communities have adapted to the small differences in climate and the environment inside the biome.

All living things are closely related to their environment. Any change in one part of an environment, like an increase or decrease of a species of animal or plant, causes a ripple effect of change in through other parts of the environment.

The earth includes a huge variety of living things, from complex plants and animals to very simple, one-celled organisms. But large or small, simple or complex, no organism lives alone. Each depends in some way on other living and nonliving things in its surroundings.

Ecological Relationships of Biomes

The survival and well being of a biome and its organisms depends on ecological relationships throughout the world. Even changes in distant parts of the world and its atmosphere affect our environment and us. The eruption of a volcano in Mexico, or Southeast Asia can bring the temperature of the whole world down a few degrees for several years.

Did you know that the Arctic Tundra is the world’s youngest biome? It was formed 10,000 years ago. Located at latitudes 55° to 70° North, the tundra is a vast and treeless land which covers about 20% of the Earth’s surface, circumnavigating the North pole. It is usually very cold, and the land is pretty stark. Almost all tundras are located in the Northern Hemisphere. Small tundra-like areas do exist in Antarctica in the Southern Hemisphere, but because it is much colder than the Arctic, the ground is always covered with snow and ice. Conditions are not right for a true tundra to form. Average annual temperatures are -70°F (-56°C).

Tundra comes from the Finnish word “tunturia”, which means a barren land. The ground is permanently frozen 10 inches to 3 feet (25 to 100 cm) down so that trees can’t grow there. The bare and sometimes rocky ground can only support low growing plants like mosses, heaths, and lichen. In the winter it is cold and dark and in the summer, when the snow and the top layer of permafrost melt, it is very soggy and the tundra is covered with marshes, lakes, bogs and streams that breed thousands of insects and attract many migrating birds.

The main seasons are winter and summer. Spring and fall are only short periods between winter and summer. The tundra is the world’s coldest and driest biomes. The average annual temperature is -18° F (-28° C). Nights can last for weeks when the sun barely rises during some months in the winter, and the temperature can drop to -94° F (-70° C). During the summer the sun shines almost 24 hours a day, which is why the Arctic is also called the Land of the Midnight Sun. Summer are usually warm. Temperatures can get up to 54° F (12° C), but it can get as cold as 37° F (3° C). Average summer temperatures range from 37° to 60°F (3° to 16°C).

The Arctic tundra is also a windy place and winds can blow between 30 to 60 miles (48 to 97 kilometers) per hour. Of the North American, Scandinavian and Russian tundras, the Scandinavian tundra is the warmest, with winter temperatures averaging 18°F (-8°C)

The tundra is basically like a desert when it comes to precipitation. Only about 6 – 10 inches of precipitation (mostly snow) fall each year. Below the soil is the tundra’s permafrost, a permanently frozen layer of earth. During the short summers the top layer of soil may thaw just long enough to let plants grow and reproduce. Since it can’t sink into the ground, water from melting permafrost and snow forms lakes and marshes each summer.

There is barely any vegetation in the tundra, only about 1,700 different species, which isn’t very much. These are mostly shrubs, sedges, mosses, lichens and grasses. There are about 400 varieties of flowers. The growing season is only about 50 to 60 days long. There are no trees, except for some birches in the lower latitudes. The ground is always frozen beneath the top layer of soil, so trees can’t send their roots down. Willows do grow on some parts of the tundra but only as low carpets about 3 inches (8 cm) high. Most plants grow in a dense mat of roots which has developed over thousands of years. The soil is very low in nutrients and minerals, except where animal droppings fertilize the soil.

Surprisingly there are animals in the tundra. Although there isn’t a lot of biodiversity, only 48 species of land mammals are found on the tundra, there are a lot of each species. These consist of slightly modified shrews, hares, rodents, wolves, foxes, bears and deer. There are huge herds of caribou in North America (known as reindeer in Eurasia) which feed on lichens and plants. There are also smaller herds of musk-oxen. Wolves, wolverines, arctic foxes, and polar bears are the predators of the tundra. Smaller mammals are snowshoe rabbits and lemmings. There aren’t many different species of insects in the tundra, but black flies, deer flies, mosquitoes and “no-see-ums” (tiny biting midgnes) can make the tundra a miserable place to be in the summer. Mosquitoes can keep themselves from freezing by replacing the water in their bodies with a chemical called glycerol. It works like an antifreeze and allows them to survive under the snow during the winter. The marshy tundra is a great place for migratory birds like the harlequin duck, sandpipers and plovers.

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.

by Whitney S. 2002

Tundra Climate 1

The tundra is a bleak and treeless place. It is cold through all months of the year Summer is a brief period of milder climates when the sun shines almost 24 hours a day. It has been called “the land of the midnight sun”. But even the sun can’t warm the tundra much. The short summer lasts only 6 to 10 weeks. It never gets any warmer than 45 or 50° F. The warmer weather causes a layer of permafrost, ice that never goes away in the ground, to melt, creating bogs and shallow lakes that don’t drain. They breed stinging insects, which make life even in the summer miserable for the inhabitants of the tundra. The wind blows constantly, whipping around the small plants.

During the long winter months the sun barely rises and it is dark for most of the day. Bitter cold winds scud across the barren snowscape, exposing high plateaus to barren ground.

Winter temperatures don’t reach above 20° F and average -20° to -30°F. Endless hours darkness settle in and the winds blow even harder. The snow that falls is blown off the high plateaus and collects in the valleys. Animals hunker down, able to find only enough food to keep warm.

The tundra is an unusually cold and dry climate. Precipitation totals 6-10 inches of rain a year, which includes melted snow. This is almost as little as the world’s driest deserts. Coupled with strong and drying winds, the tundra is an extreme weather biome. The tundra seems like a wet and soggy place because the precipitation that falls evaporates slowly, and because of the poor drainage caused by the permafrost.

You can find the tundra climate in Köppen’s E climate category. The Estands for ice climates. The average temperature of the warmest month is below 50° F.

The tundra climate spans from most of Greenland to parts of Alaska, northern Canada, and northern Russia. The latitudinal range is 75° N to 60° N. Tundra climates can be found on the coastal areas of the arctic. The ocean water keeps the climate from falling to the extreme temperatures found in the interior of the continents.

by Sam A.2000

Tundra Climate 2

The tundra is freezing for almost all of the year with no traditional seasons, only a very long winter. Winter conditions in the tundra exist most of the year, with the exception of a very short mild season which passes for summer.

The type of vegetation that grows on the tundra are; grass, shrubs of willow, sedges, and lichens. The vegetation grows very slowly because of the hard winter.

The animals in the tundra put on heavy coats to adapt to the harsh climate. Examples of this adaptation would be the coats on the caribou, reindeer, musk ox, arctic hare and the arctic fox.

The Köppen system of classification would be Dfc. D In Köppen climate classification stands up for snow climate, f stands up for sufficient precipitation in all months and c stands up for fewer than four month with average temperatures over 50° F (1°C).

The average temperature per year is 16 degrees°F. The highest temperature can get to 45° F and the coldest temperature can get to 10° F below 0. That makes it one of the coldest regions on earth. This biome feels freezing most of the year.

The average precipitation per year is more than 18 inches, and most of it falls as the snow. Average precipitation per season is 4.5 inches. The type of precipitation that falls in this climate is mostly snow in the winter, and in the summer it is rain, with occasional snow.

The latitude range for the tundra is from the arctic circle to 60° to 70° latitude North. Parts of Alaska and northern Canada contains tundra biome and climates. Tundra climate can also be found in northern Europe and Russia.

by Ilekea S. 2001.

For more information on the plant and animal life of this biome visit, http://www.blueplanetbiomes.org/tundra.htm