Portuguese 
Spanish 
New study tracked over 5,000 virtual particles and discovered that huge whirlpools transport the Congo River water for hundreds of kilometers, while other research warns of droughts, release of ancient carbon, and threats to biodiversity
The Congo River, recognized as the deepest in the world, discharges about 40,000 cubic meters of water per second into the Atlantic Ocean. Now, a study published in 2026 revealed that this fresh water can advance approximately 800 kilometers into the sea.
This represents about 40 million liters released into the ocean every second. Instead of simply mixing with the saltwater near the African coast, part of this volume is captured by huge whirlpools and transported for hundreds of kilometers.
The discovery adds an important chapter to the story of the Congo River. In addition to having sections over 200 meters deep, it influences Atlantic circulation, nutrient transport, and marine ecosystems far beyond its mouth.
-
Reels in the browser: which tool solves it without hassle
-
The digital nomad has become a global economic phenomenon: there are now about 40 million people working while traveling, a contingent that moves US$ 787 billion per year and has led countries to compete for these professionals with special visas since 2021.
-
The construction industry was one of the sectors that grew the most in Brazil in 2024, with an increase of 4.3% and a GDP of R$ 359 billion: the sector created 110,000 jobs and helped boost the country’s investment.
-
Producers took cocoa to the semi-arid region of Ceará, planted clones in Tabuleiro de Russas, tested drip and micro-sprinkling, and transformed 60 kg of beans into 45 kg of chocolate in a region previously considered unlikely for the fruit.
Whirlpool transported Congo River water for 49 days
The study was developed by researchers from the Laboratory of Studies in Geophysics and Spatial Oceanography and collaborating institutions. The results were published in the journal Journal of Geophysical Research: Oceans and released by the American Geophysical Union in July 2026.
The scientists investigated the plume of fresh water formed when the Congo River reaches the Atlantic. During the rainy season, this mass of water moves mainly southwest and can be captured by mesoscale oceanic whirlpools.
These whirlpools can have dimensions close to 100 kilometers. One of them, tracked during March and April 2016, remained active for 49 days and reached an approximate radius of 150 kilometers.
The whirlpool trapped low-salinity water in its central region and transported it about 200 kilometers away from the coast before disappearing. The phenomenon showed that the Congo’s influence on the ocean is not restricted to the mouth area.
More than 5,000 particles were tracked
To reconstruct the water’s path, the researchers used an ocean circulation model with a resolution of 3 kilometers. The simulation was compared with measurements of salinity, sea surface height, currents, and information obtained by satellites and vessel tracking systems.
The team chose 2016 because there were especially detailed observational records from that period. The model was able to reproduce the size, position, and seasonal changes observed in the Congo River plume.
More than 5,000 virtual particles were tracked retroactively. The results indicated that the water found at the center of the eddy in April had come from the southern portion of the plume during March.
The research demonstrated that transport does not occur only through slow and continuous dispersion. Episodic events, such as the formation of large eddies, can carry enormous amounts of fresh water across the Atlantic in true pulses.
This dynamic influences salinity, regional circulation, and nutrient distribution. Therefore, the results can also help understand changes in marine ecosystems and fishing areas dependent on the water brought by the river.
Depth greater than 200 meters requires caution with numbers
The depth of the Congo River is another impressive figure, but it needs to be presented accurately. It is common to find references to a maximum depth of approximately 220 meters, although this value should not be treated as an exact and definitive measurement.
Hydroacoustic measurements conducted in the Lower Congo by the United States Geological Survey identified depths greater than 200 meters. This result supports the classification of the Congo as the deepest known river on the planet.
The river system is approximately 4,300 kilometers long, depending on the criteria used to determine its source. Its basin covers about 4 million square kilometers and forms the second-largest river system in the world by flow, second only to the Amazon.
The deepest areas are in the Lower Congo, where the river traverses narrow channels, rapids, and abrupt changes in the submerged terrain. The intense currents create extreme environments and help separate fish populations.
Congo Basin shows a trend of reduced rainfall
Another study, published in October 2025 in the journal npj Climate and Atmospheric Science, analyzed 42 years of atmospheric and hydrological information, covering the period from 1981 to 2022.
The researchers identified a significant trend of reduced moisture in the central region of the Congo Basin. The process was related to lower moisture convergence and decreased precipitation, especially during the normally wetter season.
The study linked this change to the weakening of the Walker circulation and the increase in the surface temperature of the central and eastern tropical Atlantic. The ocean’s influence on regional humidity appears with an approximate delay of three months.
The air temperature in the basin has increased by about 0.17 °C per decade since the 1980s. The situation is concerning because more than 80% of the regional agricultural production depends on seasonal rains, while forests need this humidity to maintain their stability.
Dark waters are releasing ancient carbon
In 2026, another discovery drew attention to the Congo Basin. A study published in the journal Nature Geoscience found carbon from millennia-old peatlands being released by large lakes and dark water rivers.
Samples were collected from Lakes Mai Ndombe and Tumba and the Fimi and Ruki rivers. Isotopic analysis indicated that part of the dissolved carbon originated from ancient organic matter stored in the central region’s peatlands.
The results do not automatically mean that the entire carbon stock is collapsing. However, they show that ancient carbon can move from peatlands to aquatic environments and subsequently reach the atmosphere.
The discovery is significant because the region’s peatlands store approximately 30 billion tons of carbon. Changes in the hydrological balance could affect one of the planet’s largest natural reservoirs.
Small fish climb a 15-meter waterfall
Biodiversity also led to a curious discovery. In April 2026, researchers documented thousands of fish of the species Parakneria thysi climbing the Luvilombo waterfall, approximately 15 meters high, in the upper part of the Congo Basin.
The animals measured mainly between 3.7 and 4.8 centimeters. They used fins and small hook-like structures to cling to wet surfaces, advancing through areas hit by splashes.
The complete ascent can take almost ten hours. It was the first scientific record supported by images of this behavior in the species, reinforcing how much remains unknown about the animals living in the Congo River system.
Sources consulted
- American Geophysical Union — transport of Congo water through the Atlantic
- Journal of Geophysical Research: Oceans — original study of 2026
- USGS — hydroacoustic measurements in the Lower Congo
- npj Climate and Atmospheric Science — reduction of humidity in the Congo Basin
- Nature Geoscience — release of ancient carbon
- Scientific Reports — fish climbing the Luvilombo waterfall
