New research has shown algae that grow on the underside of the ice are the ultimate food source and can be traced through animals all the way up to the polar bear.
Sky News filmed researchers working on Mijenfjorden in Svalbard for the Arctic Peril documentary.
Research is showing algae produce a unique chemical called Ice Proxy 25 (IP25), which can be traced through the food chain.
Dr Tom Brown, a marine ecologist at the Scottish Association for Marine Science, said: “You can see the transfer from ice algae to zooplankton.
“You can see that fish are eating the plankton, that seals are eating the fish and that polar bears are eating seals, because IP25 is present all the way to the top of the food chain.”
Unpublished results show the chemical has been found in every one of more than 100 polar bears tested so far.
It is also present in 100% of samples taken from bearded, ringed and harp seals, and beluga whales.
The findings underline the importance of sea ice to the Arctic ecosystem.
“To have less sea ice you have less habitat for the ice algae to grow on and overall you have less supply of food from ice algae to the eco-system,” said Dr Brown.
The international group of scientists were collaborating in a research project called FAABulous.
They were studying the spring ‘bloom’, the burst of algal growth that occurs as the sun rises after the long Arctic winter.
Dr Eva Leu, a marine biologist at Akvaplan-niva in Norway, said the bloom was so important that other organisms were synchronised to take advantage.
“The crucial thing about ice algae is that they are the earliest available food source. There’s no other alternative,” she said.
“If you have an ecosystem that to start with is relying on Arctic sea ice, the question is where are these organisms going if the sea ice is completely gone?”
Mijenfjorden is the only fjord on the Western coast of Svalbard to still freeze in winter, but even there ice is melting earlier in the spring than it used to.
The latest prediction is that the Arctic will be largely ice-free in the summer by 2030.
Dr Brown said: “It’s very important to consider the Arctic as a whole. It is an ecosystem.
“There is a desire to compartmentalise everything and say ‘let’s protect polar bears.’
“Actually you need to protect everything right down to the algae.”
Arctic Peril follows cold-water swimmer and UN Patron of the Oceans Lewis Pugh on a ‘health-check’ of the polar region.
He also swims along the ice edge at 82 degrees north to highlight the speed of the melting.
He concludes that there is now runaway climate change in the Arctic.
“It’s the responsibility of our leaders who we have elected to buckle down to understand the science and take steps,” he said.
“Nothing, absolutely nothing, is more important than what is happening here right now.”
:: Arctic Peril will be broadcast on Sky Atlantic tonight at 8pm (GMT) and Sky News on Wednesday 20 December at 9pm.