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, according to a new study.

New research shows that permafrost soils hold massive quantities of mercury — nearly twice as much as is held in all other soils in the world, plus the mercury in the oceans and the atmosphere —

Severe permafrost thaw and erosion along Koyukuk River banks.