Alaska's clear rivers turn rusty: Alarming changes prompt study
Transparent and clear rivers in Alaska are turning into rusty streams. Scientists are working on finding the answer to the cause of this phenomenon. The orange hue of the water, visible from space, is indeed alarming.
24 May 2024 13:22
The once crystal-clear water flowing in numerous rivers and streams in Alaska is gradually changing its appearance. It is becoming increasingly murky, and its colour is turning rusty. Substances released into the water during permafrost thawing are suspected of causing these changes.
A team of scientists from the United States Geological Survey, University of California, Davis, and other research centers has studied this phenomenon. They analyzed rivers in Alaska that have started to change colour. This phenomenon involves previously extremely clear water bodies suddenly becoming murky and taking on a vivid rusty colour.
As part of the research, scientists collected water samples from 75 locations spread out over an area the size of Manitoba.
- 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 – says one of the scientists, Jon O’Donnell, author of the study described in the magazine "Communications Earth & Environment".
There are concerns that the observed changes could signal water contamination with toxins harmful to nature and humans. Additionally, murky water can hinder fish migration to spawning grounds. Dr. O’Donnell noticed this problem when he visited one of the rivers in 2018. However, an analysis of satellite images showed that water discoloration has been occurring since 2008.
The researcher emphasizes that the river discoloration is so significant that it is noticeable from space. Therefore, the changes are notable.
The orange water resembles that which flows out of mines, but in the area where the research is conducted, there are no mines. Therefore, scientists have hypothesized that the colour change in the water is due to the permafrost thawing caused by climate change. Minerals released from the thawing permafrost change the water's colour.
Analysis of water samples showed that in discoloured rivers, acidity and concentrations of metals such as iron, zinc, nickel, copper, and even highly toxic cadmium have dramatically increased. Iron, responsible for the change in water colour, has the highest concentration. According to the scientists, these changes are spreading gradually, from small streams to large rivers. The area where these changes are observed is constantly expanding.
To better understand what is happening in the rivers, scientists plan to conduct further studies. Researchers intend to conduct more investigations to clear up any doubts about the causes of this phenomenon.
