Arctic Ecology

The Russian Arctic: Arctic ecology

This is a teacher worksheet for Key Stage 3 geography. There are 3 questions, one of which is a food web reorganisation task. It is designed to complement a wider scheme of work either on climate change or on Russia specifically.

Curriculum relevance Understanding food webs is essential because:

• Students need an understanding of food webs: producers, consumers, and nutrient cycling • The biggest threat to Arctic species and their habitats is climate change • Millenia of evolution have prepared Arctic species like the polar bear, walrus, and narwhal for life on and around the sea ice. Now their habitat is radically shifting in a matter of decades

The Arctic food web under threat The Arctic has a diverse range of unique and endangered species. You can read about the range of animals found in the Arctic on this Arctic wildlife page.

There are recognisable mammals such as the polar bear — and the very unusual, toothed narwhal and some less-well known species like caribou and the beluga whale.

The Arctic is rapidly warming with some of the fastest changes to climate on the planet. For example, Arctic sea ice extent (the area of ocean with at least 15% sea ice) had over 2 million km² less sea ice in July 2020 compared to the 1981-2010 median average — a trend set to continue in the twenty- first century. As a result, computer models are now virtually unanimous in showing the occurrence of seasonal ice-free conditions there by mid-century.

These changes are already having a huge impact on atmospheric circulation and Arctic wildlife in the tundra. The noted loss of sea ice is extremely significant as the whole Arctic food web relies on sea ice, ice sheets and glaciers. More specifically, sea ice provides a surface for the most basic material to grow on, an organism which underpins the whole food web — algae.

Appendix A image 1 shows a simplified Arctic food web with the degrees of separation for each animal from each other.

1. Compare this image with image 2, which shows changes expected or underway in the high Arctic food web. What are the differences?

Consider the following:

a. How human activity has changed.

b. The changes in landscape that are underway.

c. Which species have declined in number.

d. The balance between marine and ice-based species.

e. The changes to algae, bacteria, and phytoplankton.

2. How many degrees of separation does a Killer whale (Appendix C) have from phytoplankton?

3. Go to Appendix B. There are 22 images of different Arctic organisms — from large fauna (animals) to microscopic flora (plants). Can you correctly reorganise them into a food web?

What might the effects of Arctic climate change be? The Arctic is very important in the fight against climate change because it acts as the ‘thermostat’ of our planet. There are several knock-on effects from climate change in the Arctic. As sea ice melts, more and more dark ocean surfaces are exposed leading to a decreased reflection of incoming solar radiation. Therefore, the ocean absorbs more heat in the form of longwave radiation, amplifying the warming and sea ice melt even further. This process is called ‘Arctic Amplification’ and explains why the Arctic is warming two to three times faster than the rest of the planet.

A longer open water season leads to increased erosion rates around estuaries and at the coast as shown in image 4, Appendix C. Thawing of permafrost might further increase methane and carbon dioxide emissions, as microbes are decomposing organic material that was locked in the frozen ground for thousands of years. The additionally released greenhouse gases also amplify the warming further.

The rapid changes in climate also have strong impacts on marine and terrestrial ecosystems. In many regions, longer and warmer summers mean a longer growing season. In some regions, this means an increased growth of nutritious plants, which has positive effects on the body condition of caribou and reindeer. But warmer summers might also lead to a regional increase in parasitic flies, forcing herds to spend hours running to escape the parasites. This means less time spent feeding and a worsening of their body condition and survival rates. Warmer winters further increase the risk of icing events. Usually, caribou and reindeer dig in the snow to access food underneath. If the snow, however, starts melting and then refreezes, or if rain falls on top of the snow and freezes, this creates an impenetrable layer of ice, and the animals cannot access the food underneath. These icing events have led to mass starvation of Arctic caribou and reindeer in the past.

Thousands of years of evolution have prepared Arctic species like the polar bear, walrus, and narwhal for life on and around the sea ice. Because of climate change, that ice cover has been changing rapidly in some areas, in both extent and thickness. What remains is younger and thinner sea ice, which melts earlier in spring and re-freezes later in autumn. There is a risk it will shrink too quickly for some populations of these species to adapt. Using computer models, scientists predict that the Arctic Ocean will be nearly free of summer sea ice by the middle of this century unless global greenhouse gas emissions are reduced drastically.

Consider the following summary points:

• A narwhal’s entire life is connected to sea ice, both as a place to feed and a place to take refuge. Slow swimming whales rely on sea ice as a place to hide from predators

• Ringed seals are having to spend more time diving for food

• Polar bears are having to spend more time swimming in the ocean

• Mother polar bears use the sea ice to hunt for seals

• Seals give birth on sea ice, upon which they build snow lairs to keep their pups warm

• The rising Arctic Ocean acidity is making it difficult for animals like crabs to build their shells

• Later freezing of sea ice delays snow accumulation making snowpack thinner and less insulated. Polar bears and seals use this to make dens and lairs for their young

• Barren ground is also shrinking, which is vital for reindeer who live on the Arctic tundra. There has already been a global population decline of 60% from the 1990s to 2017

Further information • Science key stage 2 and key stage 3:food chains and food webs in animals www.bbc.co.uk/teach/class-clips-video/food-chains-and-food-webs-in-animals/zn7g92p

• Arctic food web and climate change www.coolaustralia.org/arctic-food-web-climate-change/

• Article on how will climate change affect Arctic caribou and reindeer https://theconversation.com/how-will-climate-change-affect-arctic-caribou-and-reindeer- 86886

• Information on Arctic wildlife and climate change https://arcticwwf.org/work/wildlife/

• National Geographic Food Web https://www.nationalgeographic.org/encyclopedia/food- web/

• Geography Directions (the Society’s blog linked to scholarly journals) The UK’s response to a rapidly changing Arctic https://blog.geographydirections.com/2014/11/06/the-uks- response-to-a-rapidly-changing-arctic/

Appendix A

Appendix B

Capelin Walrus Musk Ox

Arctic hare Arctic Wolf Caribou

Arctic lemmings Polar bear Arctic fox

Narwhal Bowhead whale

Phytoplankton Arctic Tern Harp seal

Arctic owl Leopard seal Algae

Killer whale Lichen

Arctic Char Seashells Zooplankton

Appendix C

Thanks to Dr Caroline Coch (WWF-UK) for helping with the content of the materials