Important warning: Alaska's rivers turn toxic orange

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Melting permafrost in Alaska, accelerated by climate change, has turned the state's rivers into "orange dead zones," a new study reveals.

The researchers explained that iron oxides (rust) resulting from the melting of long-frozen metal ore, in addition to sulfuric acid resulting from the same process, made the fresh water in Alaska as acrid as vinegar, which led to the blackening of vegetation and the death of fish.

This orange river affects aquatic life, choking and burning it, and threatens the health and livelihoods of nearby communities.

Geochemist Dr Timothy Lyons, co-author of the study, told the Daily Mail website: “Basically, this process could happen (in theory) anywhere there are these types of rocks beneath the permafrost. These are not exceptional rocks.” "It's what we call shale, and it contains minerals like pyrite and iron sulfide, which can oxidize."

The Alaskan permafrost, which had remained frozen solid for tens and sometimes hundreds of thousands of years, reactivated ancient bacteria and released these inactive minerals into the rivers.

“They are microbes that can live under very low pH conditions, and they play a major role in iron oxidation, sulfur oxidation, and generating these acids,” Lyons said. “A lot of these reactions are catalyzed by snowmelt in wetlands.”

Using field reports and high-resolution images from the European Space Agency's IKONOS satellites, the research team documented 75 streams and 41 river wetlands across Alaska that turned orange due to this acidification.

The problem now extends from Alaska's Lower Noatak River Basin in the west, to the Arctic National Wildlife Refuge in the northeast.

What's happening in these parts of Alaska is likely to spread and persist until governments take action on climate change, said the study's lead author, Dr. John O'Donnell.

"As the climate continues to warm, we expect the permafrost to continue to melt, so wherever these types of minerals are found, there is a possibility that streams will turn orange," he added.

Lyons said the acidification of these rivers is similar to well-known pollution problems that occur when similar metals and mineral ores flow into rivers, as part of pollution from nearby mining projects.

The study was published in the journal Communications Earth & Environment.