Belly-button (IMAGE) Smithsonian Tropical Research Institute Caption Despite the fact that tropical forests are the most biodiverse terrestrial ecosystems on the planet, more is known about belly-button bacteria than bacteria on trees in the tropics. Credit Beth King, STRI Usage Restrictions Credit STRI License Licensed content 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.