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Alaska River : Change In Colour

Alaska River : Change In Colour

Rivers and streams in Alaska are changing color – from a clean, clear blue to a rusty orange – because of the toxic metals released by thawing permafrost.

  • The Arctic is warming four times faster than the rest of the world resulting in the thawing of permafrost.
  • The discoloration and cloudiness are being caused by metals such as iron, zinc, copper, nickel and lead – some of which are toxic to the river and stream ecosystems – as permafrost thaws and exposes the waterways to minerals locked away underground for thousands of years.
  • Arctic soils naturally contain organic carbon, nutrients and metals, such as mercury, within their permafrost.
  • High temperatures have caused these minerals and the water sources around them to meet as permafrost melts.
  • Permafrost is soil or underwater sediment which continuously remains below 0 °C (32 °F) for two years or more: the oldest permafrost had been continuously frozen for around 700,000 years.
  • While the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than 1,500 m (4,900 ft).
  • Around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost. This includes large areas of Alaska, Canada, Greenland, and Siberia. It is also located in high mountain regions, with the Tibetan Plateau a prominent example.
  • Only a minority of permafrost exists in the Southern Hemisphere, where it is consigned to mountain slopes like in the Andes of Patagonia, the Southern Alps of New Zealand, or the highest mountains of Antarctica


  • Alaska lies at the extreme northwest of the North American continent, and the Alaska Peninsula is the largest peninsula in the Western Hemisphere.
  • Because the 180th meridian passes through the state’s Aleutian Islands, Alaska’s westernmost portion is in the Eastern Hemisphere.
  • Thus, technically, Alaska is in both hemispheres.
  • Alaska is bounded by the Beaufort Sea and the Arctic Ocean to the north, Canada’s Yukon territory and British Columbia province to the east, the Gulf of Alaska and the Pacific Ocean to the south, the Bering Strait and the Bering Sea to the west, and the Chukchi Sea to the northwest.
  • Alaska, constituent state of the United States of America. It was admitted to the union as the 49th state on January 3, 1959.
  • The capital is Juneau, which lies in the southeast, in the panhandle region.