Looking down over the meeting of the Rio Solimões and Rio Negro from the boat
Memorable things happen when two rivers of very different provenance collide. The meeting of the Rio Solimões and Rio Negro is one of the most highly famed colliding points of the Amazon River network. The system is so large here that, at times, you are better off seeing some things happen from an airplane. Height is sometimes the only way you can appreciate how certain things work in this region: where water channels connect, or the quantity of forest that covers the drainage basin.
But, the meeting of the white and black water Solimões and Negro rivers, just downstream of Manaus, is one of the key events that you can experience a few feet from the river, i.e., on a boat right on top of it.
Google map image of the black Rio Negro and white Rio Solimões meeting to form the Rio Amazonas. Note that the rivers do not fully mix for about 50 miles after meeting, at roughly the red marker. (Ignore the blue driving path.)
The most useful comparison that comes to mind in describing this ongoing and never-ending event is adding milk to coffee. But only in the immediate aftermath of adding milk, because as we all know, coffee and milk mix quickly and create a new, uniform color within seconds after the mixing event. Unlike what we drink, the Rio Solimões and Rio Negro do not mix that quickly; their physical disparities exceed the differences between coffee and milk. The white water river, cold and sediment-loaded, rushing down from the Andes, is much denser than the black water river, sediment poor, flowing in from the lower-lying, warm rain forest of the Guayana shield. Because of this density difference, the white Rio Solimões and black Rio Negro proceed downstream side by side, unmixed for about 50 miles (according to a rough Google map calculation, shown above) after their first meeting event.
Depending on which country you are in, the mixing of these tributaries marks the official start of the main Amazon River. Other mixing events on this river boat trip have yielded similarly fantastic outcomes. To extend the metaphor, the mixing of scientists and non-scientists our river boat has paved the way for unique learning opportunities and new intellectual results, as well. Just as it was rare for scientists to have the undivided attention of a public audience, it was similarly rare for the non-scientists to witness the procession of field work and scientific debate.
Meeting room of the Premium, where group discussions and presentations took place.
For graduate students on board, it was a rich opportunity to observe their mentors step outside of typical meeting rooms and laboratories, and present results in a way that expressed their own sentiments towards why this research was important. Equally insightful was the opportunity to hear the audience react, how their attention gravitated towards certain scientific details more than others. For a week, scientists had to tell stories. And for a week, the audience had to draw from their diverse backgrounds to respond, ask insightful questions, and provide useful feedback.
For what is probably my last trip to the Amazon region for graduate school, it was fitting to end with something that was both so reflective and forward-facing at the same time. Everyone stepped off of the Premium with slightly more practice in addressing key challenges in research: how one prioritizes earth science research when funding and time are not infinite, how objective and subjective this field of science should or can be. To get better at addressing these issues surely benefits everyone involved. What awaits further “downstream” of the mixing event that occurred aboard the Premium is perhaps a better platform for communication between science and the public.