Gorgeous: Where the rivers meet

Rio Negro meets the Amazon, originally uploaded by Vilseskogen.

In the Amazon, the black-water branch called Rio Negro meets the white-water branch of the Amazon near the city of Manaus, in the middle of the rainforest. The river is so wide here that you can barely see the forest along the horizon and ocean liners can come to Manaus all the way from the Atlantic, thousands of km away. The two water masses don't mix until miles and miles downstream since they have different density. Sometimes a clump of floating grass floats by, or a log, or a pink dolphin splashes. The black water is like dark tea, full of humus and acids that gives it a low pH. This is at high water season, six months later the water level is about 6 meters lower. Forests get flooded high up on their stems, people live in houses on stilts or floats, and even the cattle are kept in floating houses and fed the floating grass during the high water. It is a different kind of life, circling around the level of the water.