Zurich researchers identify perhaps darkest river in the world
The water of the Ruki River in the Congo Basin is as dark as tea due to a high concentration of dissolved organic substances.
(Photograph: Matti Barthel / ETH Zurich)
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.
This content was published on
2 minutes
Keystone-SDA
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.
How we work
This news story has been written and carefully fact-checked by an external editorial team. At SWI swissinfo.ch we select the most relevant news for an international audience and use automatic translation tools such as DeepL to translate it into English. Providing you with automatically translated news gives us the time to write more in-depth articles. You can find them here.
If you want to know more about how we work, have a look here, and if you have feedback on this news story please write to english@swissinfo.ch.
External Content
Your subscription could not be saved. Please try again.
Almost finished… We need to confirm your email address. To complete the subscription process, please click the link in the email we just sent you.
Train vs plane: would you take a direct train between London and Geneva?
Eurostar is planning to run direct trains from Britain to Germany and Switzerland from the early 2030s. Would you favour the train over the plane? If not, why not?
Zurich arbitration authority rules in favour of tenants of ‘Sugus Houses’
This content was published on
A conciliation authority says the terminations of 105 flat leases in the so-called "Sugus Houses" in the centre of Zurich were abusive. The tenants therefore do not have to move out - at least for the time being.
This content was published on
Visitors to Switzerland spent CHF19.6 billion ($23.9 billion) last year, a 2.2% rise compared to the previous year, the Federal Statistical Office (FSO) said on Monday.
This content was published on
Despite the current tense economic situation, Swiss consumer sentiment remains positive. The Swiss spent more money in May than the previous year, particularly on restaurant visits and leisure activities, as shown by the latest figures released by PostFinance.
This content was published on
A bear killed four sheep in the Lower Engadine region near Scuol, canton Graubünden, last week. This was the first bear attack on local livestock in four years.
This content was published on
Experts believe that economic development in Switzerland will be weaker in 2026 than the forecasts made three months ago. They have also lowered their predictions for the current year.
This content was published on
Fewer people in Switzerland have a religious affiliation and the proportion who practice their religion regularly is steadily declining, a survey finds.
Study: trees have major cooling effect even in extreme heat
This content was published on
Plane trees in cities have an important cooling effect even in extreme heat, according to a new study by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL).
EPFL launches digitised version of Battle of Murten panorama
This content was published on
To mark the anniversary of the Battle of Murten on 22 June 1476, the Federal Institute of Technology Lausanne (EPFL) has launched a website that offers the public an immersive experience of the huge panorama painting of the historic battle.
77th Swiss Gymnastics Festival praised for ‘positive energy’
This content was published on
The 77th Federal Gymnastics Festival drew to a close on Sunday in Lausanne, after eleven days of popular celebration and sporting performances.
You can find an overview of ongoing debates with our journalists here . Please join us!
If you want to start a conversation about a topic raised in this article or want to report factual errors, email us at english@swissinfo.ch.