Why are rivers in Alaska turning orange?

Colombia’s Cano Cristales is known for its ‘five colours’, Amazon’s Rio Negro is known for its black water, and the Drina, which forms most of the border between Bosnia and Herzegovina and Serbia, is known for its green colour.

But have you ever heard of an orange-coloured river?

I suppose not.

Though it may appear like milky orange juice, it is bad stuff.

According to new research published on Monday in the Nature Earth and Environment journal, the drastic colour change may be because of climate change.

Let’s take a look.

Alaska rivers turn orange

Researchers have found that the affected water is in federal areas, which include national parks like Kobuk Valley and Gates of the Arctic.

More from Explainers

How ChatGPT is becoming everyone’s BFF and why that’s dangerous This Week in Explainers: How recovering from Gen-Z protests is a Himalayan task for Nepal

Scientists collected water samples from 75 sites spread across an area the size of Texas in the northern Alaskan Brooks mountain range.

Helicopters are the only means of access to several of the tested regions because they are isolated.

“The more we flew around, we started noticing more and more orange rivers and streams. There are certain sites that look almost like a milky orange juice,” lead author Jon O’Donnell, an ecologist for the National Park Service Arctic Inventory and Monitoring Network, said in a press release.

According to study researcher Brett Poulin, an assistant professor of environmental toxicology at UC Davis, some of the stained patches are so extensive that the orange rivers are visible from space.

Impact Shorts

More Shorts

Ghaziabad woman dead, pilgrims attacked in bus… How Nepal’s Gen-Z protests turned into a living hell for Indian tourists

Were bodyguards involved in Charlie Kirk’s shooting? The many conspiracies surrounding the killing

“These have to be stained a lot to pick them up from space,” Poulin said in a press release.

Researchers claim that while O’Donnell first observed a change in the water in 2018, satellite photographs from 2008 show that the water was tainted.

“The issue is slowly propagating from small headwaters into bigger rivers over time. When emergent issues or threats come about, we need to be able to understand them,” O’Donnell said.

Previously, Salmon River was identified as a specific area of concern by the National Park Service.

Before 2019, the water was considered “pristine,” according to CBS News.

The transparent water turned orange-green that summer.

The discolouration persisted, leaving orange marks on the sides of the river.

What’s behind the colour change?

Scientists believe that permafrost, or frozen land, is what is causing the hue change.

They claim that when the environment warmed, minerals kept in permafrost were released into glistening, clean water.

Acid and metals were released from the metal ores when they were exposed to air and water.

The contaminated water included high or elevated amounts of iron, zinc, nickel, copper, and cadmium, according to sample results.

The colour orange is said to be caused by iron, one of the most prevalent metals.

The affected water is noticeably more acidic because some of the water samples had a pH of 2.3 as opposed to rivers’ usual pH of 8.

Implications

The latest change could threaten fisheries and drinking water quality in the area.

A diversity of species found in Alaska’s Arctic rivers is “critical for subsistence, sport, and commercial fisheries,” according to research findings. Those fish could be at danger from iron and other harmful metals in the water.

The research added that “stream discolouration was associated with dramatic declines in macroinvertebrate diversity and fish abundance.”

“Those orange streams can be problematic both in terms of being toxic but might also prevent migration of fish to spawning areas,” O’Donnell said, in the release.

Speaking about drinking water, rural areas would need to improve their water filtration since, according to researchers, they may, at the very least, affect the taste of the water.

“There’s a lot of implications. As the climate continues to warm, we would expect permafrost to continue to thaw and so wherever there are these types of minerals, there’s potential for streams to be turning orange and becoming degraded in terms of water quality,” O’Donnell added.

According to The Guardian, scientists from the US Geological Survey, the National Park Service, and the University of California Davis are working to gain a better understanding of the long-term effects of the shifting water chemistry in areas that have continuous permafrost, which includes parts of Scandinavia and Arctic regions like Alaska, Canada, and Russia.

With inputs from agencies