Arctic Questions

Step 1: The Arctic Ocean

First, what do we know about the Arctic Ocean?

• Where is it?
• How big is it? (13 million square kilometres)
• What does most of it consist of? (Water and ice)
• For sub-Arctic residents: Who has seen the Arctic Ocean?
• What is the North Pole? (The geographical north pole is the top of the Earth’s axis, around which the stars appear to revolve. The magnetic north pole is the northern end of the Earth’s magnetic field))
• How many countries border the Arctic? (Eight - Canada, USA, Russia, Finland, Norway, Sweden, Iceland, Greenland)

Weather

• What is the weather like in the Arctic? (As warm as +18°C in summer, down to -56°C in winter).
• How many hours of sunshine are there in the Arctic summer? (Up to 24 hours)
• How many hours of sunshine are there in the Arctic winter? (As few as 0 hours)
• What happens to the sea during the winter? (It freezes up from shore to shore)
• What happens to the sea during the summer? (The ice melts in more southern areas)

Step 2: The Arctic Marine Food Chain

• How many creatures can you name, that live in or on the Arctic ocean? (Polar bears, musk ox, caribou, Arctic hares, Arctic fox, gulls, loons, terns, geese, seaducks, shorebirds, ringed seals, walrus, sea lions, beluga whales, bowhead whale, humpback whale, sperm whale, killer whale, narwhals, Arctic cod, char, salmon, capelin, herring, halibut, shellfish, crustaceans, zooplankton, copepods, amphipods, and krill, phytoplankton, diatoms, blue-green algae.) See http://collections.ic.gc.ca/arctic/species/species.htm
• What is a food chain? (Who eats who —e.g. - bears eat big fish, big fish eat small fish, small fish eat small ocean creatures called zooplankton; zooplankton eat small ocean organisms called phytoplankton; phytoplankton eat algae; algae live off energy from the sun, the water, and nutrients in the water.)
• Why is the Arctic food chain so fragile? (If one link, such as the Arctic Char, goes extinct, the whole food chain can collapse, because there aren’t so many replacement foods as in more temperate climates.)
• What is the biggest animal in the Arctic, at the top of the food chain? (Polar bear)
• What is the smallest creature, or organism, at the bottom of the food chain? (Algae)

Step 4: The Melting Arctic Ice

• Why is the ice melting? (Global warming is causing Arctic temperatures to rise very rapidly)
• Can you describe the difference between the ice extent and the ice thickness? (Width versus depth)
• Which is melting the fastest – the extent, or the thickness of the ice? (The thickness – it has lost 40% of its thickness over the past 30 years)
• What do scientists think will happen to the summer ice, if the melting continues? (It could melt away entirely by 2030 – 2050)
• What do scientists think will happen to the year-round ice, if the melting continues? (It could melt away entirely by 2100)
• How old will you be when the summer ice disappears entirely? (A 15-year old in 2005 will be 40 – 60 years old in 2030 – 2050)
• When the sea-ice melts, does it raise the level of the sea? (No)
• How old will you be when the year-round ice disappeasr entirely, if global warming continues to increase? (A 15-year old in 2005 will be 110 years old in 2110)
• How old will your children be? (Maybe 70 years old)
• How many kilograms does a polar bear lose in weight, for each week earlier that the ice melts in the spring? (10 kg)
• What do the polar bears do, if there is no ice? (Hang out on the land, and become hungry)
• What will happen to the ringed seals, if there is no ice? (They will find it really hard to raise their young in safety)
• What will happen to the diatoms and algae, if there is no ice? (They will be unable to grow, and will lose most of their populations)
• What will happen to the Arctic marine food chain, if there is no ice? (It will undergo an enormous shake-up, as some species disappear and new species move into the warmer waters)
• How do you think the melting ice is affecting people in Inuit communities, who live next to the ocean? (It is changing their hunting habits. There is more fishing from boats, less hunting from the ice, and less opportunity for snowmobiles to travel over the ice and snow - on both land and water)
• For Inuit communities: How is the melting ice affecting you?
• Why is the warming of the Arctic happening? (Because of global climate change, which is happening because our enormous planetary use of fossil fuels is releasing unprecedented quantities of carbon into the atmosphere, creating carbon dioxide, which traps the sun’s heat.)

Student Handout #1
The Arctic Marine Food Chain

A food chain shows how living things need each other for food. A green plant is usually found at the bottom of a food chain. The plant uses energy from the sun to carry on a process called photosynthesis. This allows the plant to produce its own food. This plant is called a producer. The producer is eaten by an animal, which in turn is eaten by another animal.

Since most animals eat more than one type of food, they might be able to feed from more than one food chain. However, in the Arctic food system, there aren’t a lot of different species that can be substituted.

Polar bears
(at the top of the food chain)
eat
Ringed seals, walrus, sea lions, beluga whales, and narwhals
which eat
Arctic cod, char, salmon, capelin, herring, and halibut
which eat
Small fish, shellfish, crustaceans and other invertebrates
which eat
Zooplankton, small crustaceans, copepods, amphipods, and krill
which eat
Phytoplankton
which eat
blue-green algae
which absorb
Icy water, sunlight and ocean nutrients
(at the bottom of the food chain)

5-Minute Arctic Food Chain Activity

1. Look at this food chain.
   What is the biggest animal in the Arctic, at the top of the food chain?
   What is the smallest organism (the producer) at the bottom of the food chain?
2. Using the poster paper given to your by your teacher, quickly draw a picture or diagram of this food chain. You probably don’t know what all of these animals look like. Don’t worry! Just do your best to give a sense of how the Arctic food chain works.

Student Handout #2
The Life of a Polar Bear

Read this information carefully. When you have finished reading, you will be asked (along with the rest of your group) to make up three questions to test how well the rest of your class understands the life of a polar bear. Keep this in mind as you go through the information.

Where do polar bears live?
Polar bears range throughout the circumpolar north, where they hunt seals at open leads in the Arctic sea-ice. Scientists estimate that here are about 22,000 bears in the Arctic. They live on Wrangel Island and in western Alaska, along the Alaska coast, in Canada’s Beaufort Sea, in James Bay and Hudson Bay, among Canada’s many Arctic islands, in Greenland, in Russia’s Spitzbergen-Franz Josef Land, and along the coast of Siberia. Sixty percent of the world’s polar bears live in Canada. There are no polar bears in the Antarctic - just penguins. There are no penguins in the Arctic.

How big are polar bears?
The largest adult male polar bears can grow up to three metres tall, and weigh up to 770 kilograms. Their average weight is 350-650 kg.

The largest adult female polar bears can grow up to two and a half metres tall, and weigh up to 320 kilograms. Their average weight is 150-250 kg.

How do polar bears keep warm?
Polar bears have adapted to survive in the Arctic, where winter temperatures can plunge to -45°C. Two layers of fur and a layer of blubber up to 11.5 cm thick provide such good insulation that they experience almost no heat loss. They have more problems with overheating than with cold, and they quickly overheat when they try to run. They live for 15 to 18 years.

What do polar bears eat?
The bear’s favourite hunting ground is on the Arctic sea-ice, where they hunt for ringed seals and bearded seals, (and sometimes for walrus) throughout the long dark winter. They capture the seals by lying in wait by one of their breathing holes. When the seal rises for air, the bear yanks it from the water.

What do polar bears do in the spring?
The bears eat most of their year’s food between late April and mid-July, when the ringed seal pups are abundant. They stalk the seals when they’re basking on the ice, crawling slowly forward when a seal is sleeping, and pouncing when it is about 20 feet away, before it can escape back into the sea. They also crash through the snow dens where the ringed seals raise their young and eat the pups. During this time, studies in the Hudson Bay area show that they increase their body-weight by10 kg a week. They need all the food they can get to keep their bodies warm in the year ahead, and to ensure success in having cubs.

What do polar bears do in the summer?
In July, when the ice melts, they retreat to the land. Since global warming is raising the temperature in the Arctic, the sea-ice is melting earlier. With each week earlier that it melts, the bears have less chance to feed, and come ashore 10 kg lighter. During the summer they mostly go without food, surviving on a diet of eat birds, bird eggs, kelp, and even beached whales. In areas of the Arctic where the ice is not melting so fast (Ellesmere Island, northern Greenland), the bears will remain on the ice all summer long.

What do polar bears do in the fall and winter?
In the fall, the rising temperatures affect them again. The longer the delay before the sea ice returns, the hungrier polar bears become. Biologists believe that starvation is the leading cause of death for subadult bears. As soon as the ice returns, they start hunting again and spend the whole winter out on the ice. Polar bears have been known to swim more than 60 miles without rest, in search of food. They are skilled divers, with excellent underwater vision. Where there is an abundance of ice and seals, they have a smaller range.

When do polar bears have their cubs?
A female bear usually has two cubs. After feeding heavily in August and September, she digs a den in a snowdrift along a mountain slope. The cubs are born in November or December. They are blind, toothless, and covered with short, soft fur. They grow rapidly, thanks to all the calories in their mother’s milk, which has a fat content of roughly 31%. They remain in the den until March or April, when they come out to hunt on the ice. The cubs generally stay with their mother until they are two and a half years old. Six out of ten cubs die in their first year, as a result of starvation, predation or accidents.

The polar bear is threatened not only by global warming, but also by hunting and by the accumulation of toxic industrial chemicals in the food chain.

Polar Bear Questions

Create 3 questions to test the polar bear knowledge of others in your class.

1.

2.

3.

Student Handout #3
The Melting Arctic Ice

The Arctic Ocean is one and a half times the size of Canada (13 million versus 9 million sq. km). In winter, the entire ocean freezes, and the ice stretches from Canada to Russia. In summer, when the temperature rises above 0°C, the ice melts around the southern edges.

The Arctic Warming

Since 1900, air temperatures in the Arctic have increased by 5°C, due to global climate change. Satellite data from NASA in 2003 showed that the rate of surface warming between 1981 and 2001 was eight times the warming of the previous 100 years. Some areas are warming by two and a half percent per decade. When measuring the Arctic melting, it is important to distinguish between the loss of width (or extent) and the loss of depth. It is also important to distinguish between the melting of the summer ice, and the year-round ice.

As the Arctic ice melts, there will be no impact on global sea levels, since the ice is already in the sea. Imagine taking a container of water, freezing it, and then thawing it. The water level will be the same, before and after. The concern about steady sea level rise comes from the expansion of water, as it warms. The concern about dramatic global sea level rise comes from the melting of land-based ice in Greenland and the Antarctic.

The Melting of the Arctic Summer Sea Ice Width (Extent)

The width of the Arctic sea ice is monitored by aerial photography, and by satellite. Between 1978 and 1996, it shrank by three percent per decade. The year-round ice is declining at a rate of nine percent per decade. If this continues, it will melt entirely by 2100. In 2002, there was the least summer ice ever on record. Scientists use computer modelling to see what may happen in the future. The US Geophysical Fluid Dynamics Laboratory computer model shows that the Arctic sea ice extent will fall by 20% by 2050.

If the CO₂ in the atmosphere continues to rise, by 2125 the ice-free period will increase from 8.5 to 21.5 weeks. Studies show that for each week earlier that the ice breaks up, the polar bears lose 10kg in weight, because they have less time to hunt on the ice. If half of the additional ice-free time comes in the early summer, the bears will lose 65 kg in weight.

In 1991, when the volcano Mount Pinatubo in the Philippines blew its top, it sent up so much dust that there was a temporary cooling of the whole planet. The following summer, the ice on Hudson Bay melted almost a month later. The polar bears had a whole extra month in which to hunt, and when they finally came ashore they were bigger, heavier, and their cubs survived better. The dust soon settled, however, and the rising temperatures continued. By 2002, polar bear field workers in Churchill, Manitoba, on the Hudson Bay, were reporting that the bears were skinnier and smaller, and the big 650 to 900 kg bears were no longer around.

Ian Stirling, a researcher with the Canadian Wildlife Service of Environment Canada, says that since 1980, the average weight of the female bears has dropped by up to 15%, and the average rate of reproduction has fallen from one cub to 0.87 cubs a year (a 13% fall).

The Melting of the Arctic Summer Sea Ice Depth (Thickness)

The thickness of the ice is much harder to monitor. It can be done using sonar from a submarine, or by creating elastic gravity waves from the surface, vibrations that can be used to measure the thickness of the ice. Each test gives a reading for only one spot. Now imagine doing this in an area much larger than Canada!

When the cold war ended and the US submarine data was declassified, a research team from the University of Washington in Seattle compared the data from three autumn cruises by the USS Pargo in 1993, the USS Pogy in 1996, and the USS Archerfish in 1997 with older data from 1958-1976. At 29 sites, they found that the average depth of the ice had thinned by 1.3 metres, a loss of 40%. If this rate of thinning continues, the summer ice will melt entirely by 2050.

In September 2003, a Chinese team found that the average thickness of the Arctic ice had fallen to 2.7 metres, from a previous average of more than 4.6 metres in the 1980s. This is a 42% rate of decrease in 20 years. Based on this more recent data, the summer ice could melt entirely by 2030.

The Impact on Polar Bears

The loss of the ice will have several major impacts on polar bears, and on the marine food chain:

• With each week earlier that the sea-ice melts in spring, the bears lose 10kg of weight.
• With each week later that the sea-ice freezes in fall, the bears lose more weight.
• As the ice breaks up into ice floes, the bears have to swim farther between the floes to hunt the ringed seals, burning up more energy.
• With each week earlier that the sea-ice melts, the seals have less opportunity to raise their pups.
• When precipitation falls as rain instead of snow, the dens that the ringed seals build on the sea ice can collapse, revealing the pups to the bears.
• The diatoms and algae that form the bottom of the food chain flourish at the edges of the sea-ice, where the sunlight and the water interact with the ice. As the summer sea-ice disappears, there may be fewer diatoms and algae, causing a weakening of the whole Arctic marine food chain.
• If all the Arctic ice disappears by 2100, which the computer models are predicting, the polar bears will have no ability to hunt for seals at all. Without any ice, the ringed seals and walrus will be forced to risk having their pups on land, and to live around the shores. This might provide a continued food source for the polar bears.