Biological Productivity of the High arctic ecosystem
The Central Arctic Ocean ecosystem is already undergoing fundamental restructuring from the loss of summer sea ice. Up to 40 percent of the international waters have been ice-free in two summers since 2007. This restructuring likely will affect components of the marine ecosystem differently.
For example, as waters around the edge of the Arctic Ocean get warmer, cold water species that now thrive on the continental shelf may be pushed northwards into deeper water, losing their basic habitat. The intensity of sunlight is reduced farther north and photosynthesis becomes less efficient, making conditions less suitable for some species. But reduced ice thickness also allows more light to penetrate into seawater in the spring.
Summer conditions are predicted to change much more drastically than winter conditions, creating a new environmental niche: true Arctic species will have to try to adapt to subarctic summers and subarctic species will need to survive Arctic winters if they are to shift northwards and survive.
Although the deep waters of the Arctic Basin are low in nutrients and productivity, fish, birds and mammals use this area. Removing fish and altering habitat in this sensitive environment could affect the entire food web, including ringed seals, polar bears, and beluga whales.
Documented Beluga Travel in the Central Arctic Ocean
In fact, low productivity coupled with relatively long life spans of many Arctic species means that they are highly susceptible to rapid overharvesting. Such impacts would not be limited to the offshore waters of the Central Arctic Ocean. Many of the birds and mammals observed there also migrate to and along the Arctic coast. There, they are important to the subsistence way of life for Arctic coastal peoples who have used these resources for thousands of years. If the habitat or prey of birds and mammals are disrupted in the central Arctic, the impacts may be felt by coastal communities.
In shallower waters such as the Chukchi Plateau, productivity may be able to increase more rapidly as sea ice thins and melts. During a research cruise in the Chukchi Sea in 2011, scientists found that thinning ice has greatly increased productivity in the waters below Arctic pack ice.
Thinner ice and more melt ponds atop the ice allow more light to penetrate to the water column, where phytoplankton are blooming at rates higher than previously observed. While such increased productivity may be limited to continental shelf environments where nutrients are relatively rich, it nonetheless suggests that the Arctic Ocean is capable of higher levels of biological productivity than it has seen so far. The implications for the rest of the food web remain an important subject for further study.
While such increased productivity may be limited to continental shelf environments where nutrients are relatively rich, it does suggest that the Arctic Ocean is capable of far higher levels of biological productivity than have so far occurred. The implications for the rest of the food web remain an important subject for further study.
The Central Arctic Ocean includes both deep basins and shallower continental shelves. Nearly a quarter of the area is shallower than 2000 meters, the deepest waters that can be fished with today’s technology. Of this shallower water, much of it is in the area that has lost summer sea ice in recent years. The combination of reduced ice, greater productivity, and fishable depths means that the waters north of the Chukchi Sea are likely to have the highest fisheries potential in the coming years.
More than 2,000 scientists from around the world have signed an open letter to the leaders of Arctic countries calling for the creation of an international fisheries management agreement to be put in place before unregulated fishing can damage the ecosystem.