The marginal ice zone is the area where Arctic sea ice meets open ocean. It stretches like a belt across the Arctic, thousands of kilometers long, as the extent of the ice expands and retreats throughout the year.
This ice edge is not a clear transition line and contains varying levels of ice, from smaller to larger ice floes. The amount of ice depends on wind direction and ocean currents and varies considerably from season to season, as well as year to year.
At this point you might be wondering why we care about a bunch of ice? But ice is never just ice: this area is teeming with biodiversity and is critical for the survival of many threatened Arctic species. The unique nature in this area is also essential for the rest of the globe as it supports enormous fisheries.
The source of life is a direct result of the ice retreating and expanding from season to season. During the winter the sea ice expands, and, in the spring and summer, it retreats, breaking up and letting light into the dark reaches of the Arctic ocean. This process releases an abundance of nutrients trapped in the ice and results in a concentrated phytoplankton bloom.
What are phytoplankton?
Phytoplankton are microscopic marine algae. As luck would have it, phytoplankton happens to be the base of many, many aquatic food webs. A food web connects multiple food chains. A food chain is the classic linear model that everyone is taught in school: predator eats prey.
©OlgaShpak-MarineMammalCouncil-IEE-RAS/Matt WilsonJay Clark, NOAA NMFS AFSC/Andrew Thurber-Deep-Sea and Polar Biology
But before the phytoplankton bloom happens, another vital bloom takes place underneath the ice, the bloom of ice algae. Because ice algae need less sunlight, this bloom starts approximately two months before the phytoplankton bloom. The two blooms together prolong the productive season and many Arctic species rely on this increased food source.
Sea ice is crucial habitat for polar bears, walrus, narwhal, beluga and bowhead whales, as well as ringed and bearded seals. As sea ice continues to decrease due to the climate crisis, ice dependent life, ranging from plankton to whales and polar bears is also likely to suffer. By 2030 the Arctic Ocean is projected to be ice-free.
As the extent of Arctic sea ice shrinks because of climate change, there is growing pressure to allow for greater oil and gas exploration, particularly in Norway. Norway cultivates an international reputation of sustainability, but it is also Europe’s fossil fuel powerhouse; the government is planning to put this valuable Arctic area at risk in a quest for more oil.
Protecting the ice edge
Norway is currently updating its management plan for the Barents Sea and considering policies that are important to the future sustainability of this critically important Arctic ecosystem. The latest scientific advice given to the Norwegian government recommends expanding the management area of the marginal ice zone. But the Norwegian government is under a great deal of pressure to ignore the science and instead reduce the size of the marginal ice zone’s management area. This would make it harder for the government to declare this vitally important area a no-go-zone for offshore development, and easier for companies to continue searching for oil within this important and unique biological area.
Sustainability is the key to getting it right from the beginning.