Editor’s note: Call to Earth is a CNN series committed to reporting on the environmental challenges facing our planet, along with the solutions. Rolex Perpetual Planet Initiative has partnered with CNN to promote awareness and education around key sustainability issues and inspire positive action.
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The Congo Basin in central Africa is one of the largest remaining wilderness areas on Earth, spanning 3.4 million square kilometers (1.3 million square miles). It is home to over 10,000 species of tropical plants and more than 2,000 species of animals β many of which are unique to the region.
As Africa’s largest river basinit crosses the borders of many countries and is one of the largest in the world coal sinksabsorbing carbon from the atmosphere and locking it away.
Despite its importance, much of it remains undocumented for science. As temperatures continue to rise globally and weather patterns change, understanding the basin and its ecosystems is vital for scientists and local communities to conserve these areas and build resilience to climate change.
Steve Boyes, founder and project leader of The Wilderness Project, collects scientific information along the entire length of the Congo River. It is part of the Great Spine of Africa research expeditions, in collaboration with the Rolex Perpetual Planet Initiative, which started in the Okavango Delta and will also include research in the Zambezi, Nile, Chad and Niger river basins.
“There is magic, there is mythology, there is power in these rivers,” Boyes told CNN. “It’s the unknown. And this is every corner, typically, of these rivers.”
Boyes has dedicated his life to exploring the science of Africa’s freshwater systems. His research in Botswana’s Okavango Delta in 2014 helped the river gain status as the 1,000th UNESCO World Heritage Site and was instrumental in the discovery of more than 140 new species, as well as a new source for the delta’s highlands Angola.
This expedition is not the first time Boyes has explored the Congo Basin. In 2023, together with a team from the National Geographic Okavango Wilderness Project, he made a 39-day canoe trip on the Cassai River in Angola, covering more than 754 kilometers (469 miles) and showing that the Munhango River is the main source of the Cassai.
In April and May of this year, the Great Spine of Africa team worked extensively along the Congo-Zambezi water tower (a term referring to a forested catchment with high water storage potential) covering the Chambeshi River in the Northern District of Zambia β the most remote source of the Congo. The 33-day journey downstream was the first scientific expedition ever to attempt to travel the length of the Chambeshi and record its landscape and communities.
Traveling in five canoes, the team of 10 collected data on everything from birds to settlements, boats and bridges to create a comprehensive snapshot of Chambeshi’s vast ecosystem. Along with 71 aerial drone surveys, water quality measurements and pathogen samples, they took nightly recordings of bats and measured water flow to see how the river is evolving as it makes its way across the country.
They also stopped at regular intervals to monitor fish biodiversity and sample environmental DNA (eDNA) released into the water by different organisms.
Call to Earth: The Great Spine of Africa
“The eDNA will show us what the aquatic diversity is in the river,” explained Chambeshi mission lead researcher Matt Dooley.
βIn some of these riversβ¦ the diversity is incredible and there aren’t many people in the world who really know all the fish that we collect. So we often find new species or subspecies of fish. And the Chambeshi River in particular is very poorly sampled in terms of fish diversity.”
The team caught, sampled and photographed about 50 species of fish, which will be sent
for analysis to confirm whether they are new species or subspecies, undiscovered to science.
Once a mission is completed, the collected data is uploaded to the cloud and made accessible to any researcher who wants to use it. Findings are also collated and distributed to local authorities, NGOs and communities to better understand the nature of the river and where it might benefit from increased protection measures.
“It’s not just going down and taking pictures and looking and meeting people,” Boyes said. βThese are the most detailed, hydrological, ecological baselines of rivers that have ever been done anywhere on Earth.
“We’re doing this for future scientists.”
Exploring the ‘Great Spine of Africa’