The Arctic TundraA treeless area between the icecap and the tree line of arctic regions, having a permanently frozen subsoil and supporting low-growing vegetation such as lichens, mosses, and stunted shrubs. is a very unique habitat with its own defining food web. I will be focusing on the Arctic tundra found in northern Alaska since that is where the Toolik Research Station is located. This biome has long cold dark winters and short cool summers with 24 hours of daylight. It has low precipitation and dry winds. The most unique part of the Arctic tundra biome is the permafrost or ground that is permanently frozen. Its frozen and no roots or water can get through. During the summer it starts to thaw on top and this is called an active layer. Within this layer, plant roots are now able to grow and insects can burrow into it.
Decomposers, like fungi and bacteria, complete the food chain. Decomposers turn organic wastes, such as decaying plants, into inorganic materials, such as nutrient-rich soil. They complete the cycle of life, returning nutrients to the soil. This starts a whole new series of food chains.
Hi DJ! Really nice job with the food chain and web journal entry! I'll show it to my students! I also like the Nat'l Geo link, I hadn't seen it before so thank you! Looking forward to learning about the microbial habitat in the tundra! I haven't been to Toolik, but from my PolarTREC friends, it sounds like an amazing hub for Polar research! Enjoy!
The example below shows the energy flow in a basic food chain in The Tundra. This food chain is part of a more complex food web involving producers and consumers (herbivores, carnivores, and omnivores).
2/ Whales tap the food chain low down - close to the producers, there are few steps and so little energy is lost meaning more is available to the whales, so they are able to grow to enormous sizes. The higher up a food chain you get, the lower the biomass of animals (that is number of animals multiplied by their weight) because there are more steps and so more energy is lost. The more steps in a chain means less food available at the top, no more than 10% is ever passed on from one step to the next, often much less.
There are few land plants in Antarctica, all the large animals including the ones that come onto land like seals, penguins and other birds take their food from the sea. The producers in Antarctic food chains are tiny single celled plants known collectively as phytoplankton that float in the upper layer of the sea though they can grow at depths down to about 100m.
Up at the northernmost point of the earth lies an extremely cold environment, the Arctic Circle. Enclosing the North Pole, the Arctic region of the earth is so cold that the land below the surface of the earth is permanently frozen. In this part of the world, we find a biome known as tundra, which is characterized by its very cold temperatures and low levels of precipitation. It is, essentially, a frozen desert. For this reason, it may not be surprising that the numbers and diversity of living organisms here are both quite low. However, there are some hardy types that can survive in this environment, creating their own unique ecosystem and food chains.
Every ecosystem consists of plants, herbivores, and carnivores. Food chains identify who eats whom to demonstrate the flow of energy in a oneway, linear relationship. For instance, along the coast of the arctic tundra, phytoplankton is at the bottom of the food chain. Zooplankton eats the phytoplankton, cod eats the zooplankton, harbor seals eat the cod, and polar bears eat the seals. Polar bears, in this food chain example, would be the apex predator (i.e., top of the food chain).
But life within any ecosystem is much more complex than the food chain we just examined. That is why biologists use food webs to understand the multiple ways in which energy flows among the members of a given landscape. In reality, herbivores eat multiple types of plants, and predators eat multiple types of prey. In fact, many animals are omnivores; eating plants, vertebrates, and/or invertebrates.
The population of animals in the tundra fluctuates throughout the year. During the summer, the sunlight hours increase significantly, affording plants more time to grow. The melting snow creates bogs and marshes that support plant growth, thirsty animals, and the life cycles of insects. Newborns grow quickly in the summer to prepare for the impending, long colder seasons. Many birds migrate to warmer climes in search of food during the fall and winter. The animals that remain have lots of fat reserves and fur to stay warm. Many of these year-round residents either hibernate (i.e., sleep for many weeks at a time, like the pika) or enter winter lethargy (i.e., sleep and briefly wake to eat, like polar bears) to reduce their need for food. Other year-round residents, like the arctic fox and arctic hare, remain active during the winter. Arctic foxes cache bird eggs in the snow to dine on them when lemmings are harder to find. Arctic hares eat snow to stay hydrated and shelter in grassy nests atop high rocks.
Tundra inhabitants are specially adapted to the environment. Some animals stay active year-round. Other animals sleep most of the winter, via hibernation or winter lethargy, or migrate to warmer landscapes in search of food. Food chains do an excellent job of illustrating the different trophic levels of an ecosystem, but food webs reveal the more complicated inter-relationships among primary producers, consumers (primary, secondary, tertiary, and quaternary), and decomposers (also called detritivores). Primary producers harvest energy from the sun, water, soil, and air to create edible foods rich in nutritious energy. Herbivores and omnivores eat the producers, and predators eat the primary consumers, and even the secondary and tertiary consumers as it goes up the food chain to reach the apex predator. Detritivores ensure the nutrients and energy of all dead organisms return to the soil by decomposing the organisms into simpler components.
A food chain is a representation of the energy flow through the organisms that live in an ecosystem. Energy ultimately comes from the sun, which provides the light energy to power the process of photosynthesis. Autotrophs are the living organisms that have the ability to undergo photosynthesis in order to make their own food. They are also called producers, as they make food for all of the other organisms in the ecosystem.
Producers are at the bottom of the food chain, in what is called the first trophic level. The producers in the Arctic tundra are scrubby bushes, grasses, mosses, and lichens. Lichens are the most abundant, and they are unique organisms made up of fungi and algae that are connected in a symbiotic relationship. All of these organisms are able to convert light energy from the sun into chemical energy that is stored within the bonds of the sugar they create, which is glucose. All of the organisms that ingest or absorb the glucose receive this energy.
Primary consumers are the animals that eat the producers. They are also known as herbivores, and they represent the next trophic level. In the Arctic tundra, these organisms are insects, small mammals known as pika, the Arctic hare, and the large caribou. All of these animals receive the energy stored in the glucose made in the plants. Secondary consumers eat the primary consumers. They are animals such as the Arctic fox and snowy owl. Tertiary consumers are at the top of the food chain; they can eat both secondary and primary consumers and are the largest animals such as the polar bear and Arctic wolf. Finally, decomposers such as fungi break down all of the dead and decaying organisms in the area. This process is very important, as it releases nutrients back to the earth to be recycled.
A food chain demonstrates the energy flow among the organisms that live in the Arctic tundra. The producers in this ecosystem are lichens, as well as mosses, grasses, and shrubs. Primary consumers are herbivores such as insects and Arctic hares. Secondary consumers are the Arctic fox and snowy owl, tertiary consumers are the polar bear and Arctic wolf, and decomposers include fungi. 2b1af7f3a8