ETH Zurich researchers study one of the world’s darkest rivers
They set out to study the Congo Basin’s carbon cycle and in the process have become aware of one of the world’s darkest blackwater rivers: the Ruki. In the first study on this major jungle river, an international research team led by ETH Zurich explains how this blackness comes about and what it says about the river system’s carbon balance.

In brief
- The Ruki River in Congo is one of the darkest blackwater rivers in the world due to its high content of dissolved organic matter.
- The organic matter comes mainly from forest vegetation.
- Peat bogs along the river currently release very little organic matter into the Ruki because the bogs are submerged for most of the year.