The Impact of Climate on the Nature of Cold Environment Ecosystems

Climate is the average weather conditions of a place usually measured over a year; cold environments tend to have a climate of low temperatures, frequent precipitation (in the form of snow) and strong winds, an example of a cold environment is Alaska in Northern America. Cold environments have high latitudes and altitudes; Alaska is 70 degrees North of the equator.

The annual temperature of Alaska is -12.7 degrees and winds can reach up to 97km per hour, due to this typical climate of cold environments ecosystems can suffer here, therefore plants and animals must adapt, food webs decrease in trophic levels and the nutrient cycle is affected due to nutrients not being readily available. Alaska also has two main climatic regions, an ice Tundra and a cold boreal environment, the cold boreal environment is characterised by forest areas and the ice tundra is characterised by thick ice sheets. One of the ways in which climate impacts the nature of cold environments ecosystems is the nature of plants, because of these impacts there are only 28 different species of plant in Alaska. Due to low levels of sunlight the plants which grow here tend to hand dark leaves for maximum photosynthesis (so that they can absorb energy), most plants here are also evergreen so that they do not need to grow leaves before beginning photosynthesis for maximum light capture. Alaska is 70 degrees north of the equator and therefore has a lack of direct sunlight due to the areas high latitude because it means that the sunlight rays are spread over a larger area than a climate with low latitude, meaning that plants here produce more chlorophyll (have dark green leaves) to absorb maximum light. Due to lack of nutrients in cold climates most plants here have a short growing season and store food in tubers and rhizomes allowing rapid growth in spring. Due to the typically low temperatures in cold environments most plants here have adapted to grow closely together to form microclimates in-between them which can extend their growing season by 5-10%, an example of a plant which has this adaptation are cushion plants. Due to strong winds (which can reach up to 97km per hour) plants found here typically are low growing and glow close together to form a microclimate, which reduces wind speed by 99%, and form a waxy cuticle to prevent water evaporation. Due to high levels of precipitation in these types of environments (snow cover) plants have adapted to store food in tubers so that they are able to survive  while being covered with snow with little or no sunlight, due to these plants can survive for up to 2 years under the snow. This highlights how the harsh climatic conditions in Alaska have forced plants to adapt to survive and reproduce successfully.

A second way in which climate impacts the nature of cold environments ecosystems is the of nature of animals that live in these environments, for example the Arctic fox found in Alaska. In Alaska the average temperature is -12.7 degrees annually and winds can reach up 97km /hour therefore to survive the arctic fox has adapted to have thick fur to trap air and a layer of fat for insulation. The arctic fox is also white in colour therefore it is camouflaged with the snow and so has adapted to not be seen by its four species of predator, the arctic fox is also able to change colour to brown during the summer and winter months to blend in with its surroundings. Another way in which the arctic fox is able to keep warm is having greasy hairs to repel water so that the fox does not become cold due to the evaporation of water from his skin. Another animal that has adapted to the harsh conditions in Alaska is the caribou. The caribou must thrust their muzzles into snow to sniff for food or to push snow aside to find food, therefore caribous muzzles are densely covered with short hairs to help warm the intensely cold air before it is inhaled into the lungs. The caribou also has large feet and 4 toe which offer stable support on wet, soggy ground and on crusty snow allowing the caribou to run from predators in all conditions. Another adaptation that the caribou has for living in snowy conditions such as Alaska is having a fantastic sense of smell. Low-growing lichen is key to the caribou's winter survival; a hungry caribou can sniff out a lichen plant from as much as 5 metres under the snow. The caribou must also adapt to survive on a low energy diet during the winter as the plants contain little energy due to low sunlight levels, therefore the caribou has a specialised 4 chambered stomach and a complex digestive system which allows them to thrive on vegetation such as lichens, they are able to digest every bit of nutrients possible out of the foods they eat and therefore can gain maximum energy from their food. This highlights how the harsh conditions of cold environments have forced animals to adapt to survive and reproduce successfully.

Another way in which climate impacts the nature of cold environments ecosystems is the nature of the nutrient cycles in these environments. Most nutrients are stored in the litter layer (organic horizon) including potassium and nitrogen this, which are essential for plant growth, this is because due to the such low temperatures in Alaska microbial activity is limited therefore decomposition is slow and so biomass is the smallest nutrient store found in Alaska. However due to low temperatures (-12.7 degrees annually) permafrost forms on top of this layer therefore water cannot peculate and so there are little nutrients in the soil (as water carries nutrients). Permafrost also makes it difficult for plants to lay down roots therefore there is little biomass in these types of environments. Also due to cold temperature rates of weathering are slow therefore there is little freeze thaw or hydrolysis taking place making decomposition and bacterial activity slow, and so there are little nutrients in the soil layer. The low levels of precipitation in these types of environments also results in low levels of leaching therefore nutrients cannot dissolve into the soil layer making it difficult for plants and animals to survive here as there is little nutrients for them to absorb. Due to the large little store in Alaska because of the slow decomposition and small biomass layer rate plants have adapted to have shallow roots to absorb maximum trients. This highlights how the climatic conditions have forced plants to adapt to survive and reproduce successfully.

Another way in which climate impacts the nature of cold environments ecosystems is the nature of food webs and biodiversity, food webs in biodiversity have very few trophic levels because energy is lost at each trophic level because each level contains little energy to be absorbed, therefore to conserve energy the food webs are short (usually about 3 levels) and so there is little biodiversity in cold environments. However the reality in a complex food web in the distinction between herbivores and predators is blurred; most species take a wide variety of food, depending on what is available (the food webs are interdependent), therefore the top predators take a wide variety of food and many resort of feeding on insects and plants when their main food is in short supply, wever this also meant that when one species is failing other species fail due to the boom and bust cycle. Lemmings and other small mammals form a key food for many predators in Alaska. Large fluctuations in lemming populations may are a problem for predators, which depend on them to meet the demands in their young during their breeding season causing the lemming predator numbers to decrease along with the lemming population. This emphasises that the climate is the driving force affecting the nature of cold environment ecosystems as the low temperature and low moisture levels mean that the process of decay is significantly  inhibited so there is a large litter layer made up of decomposing plant material, and so overall the climatic conditions of Alaska.

In conclusion This emphasises that the climate is the driving force affecting the nature of cold environment ecosystems as the low temperature and low moisture levels mean that the process of decay is significantly inhibited so there is a large litter layer made up of decomposing plant material, and so overall the climatic conditions of Alaska, a cold environment has forced both plants and animals to adapt in a variety of ways to survive and reproduce successfully.