PLANET EARTH Freshwater
Most rivers do not end in lakes but continue their journey to the sea. The planet's indisputable（毋庸置疑的） super-river is the Amazon. It carries as much water as the next top-ten biggest rivers combined. Rising in the Peruvian Andes（秘鲁安第斯山）, its main trunk flows（主干流，与之相反的是支流，见下文tributary） eastwards across Brazil（巴西）. On its way the system drains a third of South America. Eventually, over 4,000 miles from its source, it empties into the Atlantic Ocean.
The Amazon transports a billion tons of sediment a year, sediment clearly visible at the mixing of the waters where one massive tributary（支流，与上文主干流相对）, the Rio Negro（里奥内格罗，位于巴西）, flows into the main river. Its waters are wonderfully rich. To date over 3,000 species of their fish have been described - more than in the whole of the Atlantic Ocean. The Amazon is so large and rich in fish that it can support fresh water dolphins（淡水海豚）.
