Amazon River (IMAGE) University of Arizona Caption One of the world's longest rivers, the Amazon is known for its exceptional biodiversity. Contrary to conventional wisdom, which has associated species richness mostly with tropical regions, UArizona ecologists found that freshwater habitats in general tend to boast high biodiversity considering their tiny area compared to terrestrial and ocean habitats. Credit Neil Palmer/CIAT (Wikimedia Commons) Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.