Why is Part of the Amazon River Black? Wisconsin Spooky Lakes Expert Explains

Why does water turn black? There are incidents of water freezing black in some terrifying stories on TikTok, but they’re not always an unexplained, paranormal phenomenon. Geo Rutherford (@geodesaurus) from Wisconsin, an expert on spooky lakes, explains.

Madison Orlando, another TikTok user, posted a video of herself and her friends swimming in the Amazon River. She seemed to be enjoying her swim until she realized that the water was dark—almost black. Is this deadly pollution? Or worse, maybe this is where brain-eating amoebas live? There must be some sort of witchcraft turning the lake dark—except it’s not exactly witchcraft.

Upon closer inspection, the water is less black and more stained—similar to extremely strong black tea,” Rutherford explained on her stitched TikTok.

But what’s draining into the river? Dead animals sacrificed to the gods?

“This coloration is the result of highly soluble tannins, which leached into the river stream or lake. These tannins come from decaying vegetation, such as leaves, bark, wood, or peat,” she added. Essentially, the part of the Amazon River that’s been stained brown isn’t made from the blood of orphans or dead, sacrificed animals. It’s foliage from the rainforest leaching into the river. It’s almost as if nature turns parts of the river into tea cups filled with tea—not so scary when that’s the reality of it.

“Not only do the tannins make the water dark, but they also make it more acidic, generally changing the water chemistry and ecology,” Rutherford expounded. This isn’t so spooky either—”acidic” doesn’t mean people will dissolve the moment they plunge into the water. Instead, it can soften the skin, because tannins have astringent properties.

TikTok is still creeped out by blackwater

“Historians actually know that colonists and mariners would fill barrels from blackwater rivers. It was a safer source of drinking water in times before treated water, even if the colonists didn’t know why it was safer,” the lake expert cited. As previously said, blackwater has a different chemical makeup. Because of its darker appearance, light gets filtered into the water, which prevents algae blooms. Coupled with the acidity, pathogens are less likely to survive in natural blackwater.

Rutherford made an example of the Rio Negro in the Amazon, which is one of the cleanest rivers in the world. Despite its dark waters, it’s notably one of the cleanest rivers in the world.

But rivers being stained black isn’t an exclusive phenomenon to the Amazon River. Rutherford also mentioned an incident in Florida, where the river’s dark waters met the ocean. A photo of the Suwanee River in Georgia that looked polluted from space was also just another case of staining.

When all is explained, the river turning black because of tree bark isn’t the scariest thing ever. But it seems that blackwater still doesn’t sit well with TikTok users even after Rutherford’s explanation. One commenter said, “The color of the water is the LAST thing I’d be worrying about if I somehow ended up in the Amazon River.”

Granted, the Amazon River is home to the notoriously carnivorous piranha. The fish are home to the Amazon River basin, including the Rio Negro. These fish are known to attack when there is disturbance and struggle in the water.

So, the water isn’t what’s scary—it’s what lurks beneath it.

(featured image: Noa de Angelis)

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