Imagine living in a sauna. That is Ciudad Guayana, in the middle between the Orinoco and the Caroní River. The city is located in a beautiful area, but the whole region is under a lot of environmental strain (oil, mining, illegal logging, no proper treatment of residual waters).
The Orinoco is a "white" and the Caroní a "black water river". The dark colour in "black rivers" derives from humic acid due to incomplete breakdown of phenol-containing vegetation of sandy areas. Alexander von Humboldt described the differences over 2 hundred years ago when travelling through the Orinoco to the Río Negro and from there to the Casiquiare and back to the Orinoco. Some mosquitos thrive in white water rivers and not so much in black ones, as any traveller there very soon notices.
The Orinoco is a "white" and the Caroní a "black water river". The dark colour in "black rivers" derives from humic acid due to incomplete breakdown of phenol-containing vegetation of sandy areas. Alexander von Humboldt described the differences over 2 hundred years ago when travelling through the Orinoco to the Río Negro and from there to the Casiquiare and back to the Orinoco. Some mosquitos thrive in white water rivers and not so much in black ones, as any traveller there very soon notices.