In the heart of the biggest tropical forest of the world: the Amazon Forest. This forest covers one third of the South-American continent, nearly the surface of the United States. The flora and fauna constitute an exceptional heritage with several million species. Fred, Jamy and Sabine are taking part in the meeting of scientists of the National Scientific Research Center CNRS, who are working in the middle of Guyana, in a primary forest which has never been influenced by human beings. Thereby multiple questions regarding biodiversity, climate, and nutrient uptake … are posed and answered.