One in three US rivers have changed color since 1984. Here's what this means

[marmar]

One in three US rivers have changed color since 1984. Here's what this means
Blue bodies of water in the United States are turning to jaundiced yellow and even greenish hues

By MATTHEW ROZSA
JANUARY 3, 2021 3:00PM


(Salon) Anew study reveals that roughly one out of three large American rivers have appeared to change color since 1984, with many of the bodies of water seeming to slowly turn yellow and green — and scientists tell Salon that this could mean some very bad things for human health.

Analyzing approximately 15.9 million satellite images taken over a period of more than three decades, researchers at the University of North Carolina at Chapel Hill, the University of Pittsburgh and Colorado State University discovered that of the more than 108,000 kilometers (roughly 67,000 miles) of rivers at least 60 meters (197 feet) wide studied throughout the country, 56% appeared predominantly yellow and 38% appeared predominantly green. While rivers often change color based on the seasons and flow regimes, the scientists found that one-third of rivers had experienced long-term "significant color shifts" between 1984 and 2018.

"One thing to remember is that rivers are not necessarily turning 'yellow' or turning 'green,'" Dr. John Gardner, a co-author of the study (which was published earlier this month in the scientific journal Geophysical Research Letters), wrote to Salon. "If you recall to visible light spectrum R-O-Y-G-B-I-V (red, orange, yellow, green, blue, violet), a significant 'red-shifted' trend simply means that there is a trend towards the red yellow end of the spectrum, which could mean a river is changing from green-blue to green. Similarly, a 'blue-shifted' trend means a river is trending towards the blue/green end of the spectrum, which could mean a river is changing from yellow-orange to yellow, or green-yellow to green."

....(snip)....

The end result is that "if a river changed from green to yellow, that would likely be caused by some combination of less algae and more suspended sediment. Potential drivers of such changes are numerous, spanning changes to the river channel itself to how entire landscapes are managed." Gardner observed that increased construction due to urbanization, increasing river flows and agriculture can increase suspended sediment and make a river appear more yellow, while a decrease in nutrients and light can reduce algae and make a river appear less green. .............(more)

https://www.salon.com/2021/01/03/one-in-three-us-rivers-have-changed-color-since-1984-heres-what-this-means/

[Arne]

1. OMG Marmar, rivers? Look at the Gulf of Mexico.

Where I live, our world class beaches are chocked with dead sea life.
On the Gulf you will cough and cry.

[abqtommy]

2. Is it time now to start a Blue Rivers Matter movement? snark off but you get the point