kayak the Congo river
A few years ago a museum curator took a team of researchers on a fact finding expedition to Africa. When they got there they kayaked the Congo. Was Indiana Jones the curator? Melanie Stiassny, the Curator of Fishes at the American Museum of Natural History, was looking for evidence of evolution still evolving.
The Congo might be the most unusual river in the world. It hides several secrets under the mud dark water. You’ve seen enough rivers to know what a river bed looks like. This one doesn’t like the ones in your imagination.
In the novel, Heart of Darkness, Joseph Conrad described a night on the Congo, The dusk came gliding into it long before the sun had set. The current ran smooth and swift, but a dumb immobility sat on the banks. The living trees, lashed together by the creepers and every living bush of the undergrowth, might have been changed into stone, even to the slenderest twig, to the lightest leaf. It was not sleep — it seemed unnatural, like a state of trance. Not the faintest sound of any kind could be heard. You looked on amazed, and began to suspect yourself of being deaf — then the night came suddenly, and struck you blind as well. About three in the morning some large fish leaped, and the loud splash made me jump as though a gun had been fired. When the sun rose there was a white fog, very warm and clammy, and more blinding than the night. It did not shift or drive; it was just there, standing all round you like something solid. At eight or nine, perhaps, it lifted as a shutter lifts. We had a glimpse of the towering multitude of trees, of the immense matted jungle, with the blazing little ball of the sun hanging over it — all perfectly still –
Farther down the river, a hundred years later, the kayaks came. Paddled by a team of scientists to map the underwater mysteries, take DNA samples, and study the fish that live there.
It took several years.
They found more than fish.
There are two reasons to kayak the Congo. It has world class rapids, and it’s a good way to see into the unfathomable fathoms of the deepest river in the world. The little northern boats are a perfect place to put echo equipment to map the river floor. You can’t swim in it, the water is more dangerous than the fish.
Hiding beneath the dark surface are canyons and walls that drop down more than 500 feet, whirlpools that come and go, and undertows that you might only expect to find in the ocean. In some places, the conditions in the river are so extreme, the fish living on one bank don’t cross the river to the bank on the other side. The evidence of this is in the DNA. There are two species of fish which look identical on the outside but they have 122 differences in their genetic markers. In terms of evolution this is a 5% change. One cousin lives on the east bank. The other lives on the west bank, 2 kilometers apart, but they’re isolated from each other. They don’t travel very far up and down the river and they don’t cross it.
Why do the fish not cross the river? To not get to the other side.
Why is this river so unusual? The answer is hydrological.
It’s as logical as the rocks and minerals the water cuts through. Water shapes river beds by cutting away the topsoil and eroding stone. The character of the rocks in the river bed decides the shape of the caverns and cave formations. Some stone is softer than others.
Think of the grand canyon. The cliffs rise up the sides of the river, above the surface, where you expect cliffs to be. Now imagine cliffs where you don’t expect them to be. Imagine building a dam across the Snake river, 500 feet up the cliff sides. This wall is a two-sided cliff across the current of the river. Then build another farther down the river. Then another. Then another. Build them at different heights and widths. Change the shapes, and put them in random locations. Some very close. Some far apart. Then dig a deep cave in an unexpected place. Maybe in the floor of the river, maybe in the walls of the cliff sides. The locals find blind fish washed up on the river banks. So we know there is at least one deep cavern in the river with perfect blackness and no light.
Is this what you expect a river floor to look like?
The unusual geology under the waters of the Congo has created multiple ecological systems – different neighborhoods for the fish to live in. Each unique fish population has adapted to live with his peeps in the different ‘hoods of the river. Evolution is rich, diverse, and continuous in these waters. That’s what Melanie Stiassny went there to see. The isolation which assists evolution.
Open the clouds, turn up the rains, and let the water flow. Fill the canyon with water so deep, that it moves swiftly over the caverns and cliff sides, and so dark that it hides everything. It’s a mysterious place of shallows and deeps which you can’t enter. The Congo flows from the heart of Africa, the rift valley, across the plains, through the jungle into the Atlantic Ocean.
In each of the box canyons and caves there are different species of fish. They don’t go up and down the river because each neighborhood is different and each fish becomes a specialist there. Some neighborhoods are rough, some are calm. Some fast. Some slow. Some black, Some light.
As you ride the rapids in the kayak, sometimes the deepest water beneath you flows in the opposite direction. This happens in the canyons. When the water comes to a wall, some goes over, some goes down, and rolls back up again, The water rolls over itself in deep places, like a wave on the surface. This pushes the water higher and makes rapids, whirlpools, and waves. In most other rivers the rapids are in the shallows, and they don’t have whirlpools.
In the rainy season 50,000 cubic meters a second flows from the Congo River into the sea.
From all the rivers in the world how much water flows into the sea every second?
The same amount of water rises into the sky every second to fall as rain into the rivers again. The rain from a single cloud weighs tons. Fill a bucket. Water is heavy. The sky is amazing. Water is the food of life.
Genetics, Geology, and Hydrology.
Need an excuse to fly to Africa and kayak the rapids of the Congo? Become a curator at the museum. Tell them it’s your job.
To meet the fish and watch the waters churn, visit the American Museum of Natural History and listen to Melanie Stiassny tell her story.
See a 1915 slide show of the monkey’s that live in the Congo. Bring your imagination. When these pictures were taken there were no nature shows, no T.V., and only one way into the jungle…