Zurich researchers identify perhaps darkest river in the world
Zurich researchers have identified one of the darkest rivers in the world. The Ruki River in the Democratic Republic of Congo is darker than the famous Rio Negro in the Amazon, ETH Zurich announced on Wednesday.
An international research team led by the Swiss Federal Institute of Technology Zurich (ETH Zurich) conducted a study to investigate why the river is so black. According to the university, this is the first study on the jungle stream.
The result: The water of the Ruki is so dark because, due to its low gradient, it carries hardly any sediment, but large amounts of dissolved organic substances. According to ETH Zurich, its water contains four times more organic carbon compounds than the Congo River and one and a half times more than the Rio Negro in the Amazon.
According to the university, the carbon-containing substances enter the river primarily in rainwater. The rain falls on the dead jungle vegetation, dissolving organic compounds from the dead plant material, the study published in the journal “Limnology and Oceanography” showed.
In addition, the river floods the forest in the rainy season. The water then often sits waist-high on the forest floor for weeks and only drains away very slowly. The water becomes enriched with organic substances. “Ruki is actually jungle tea,” explained ETH researcher Travis Drake in the university’s statement.
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