How are biological communities organized and functioning? How environmental change affects the communities functioning? These questions are at the heart of advances in the understanding of energy and matter flows on Earth. The Ecosystems Ecology is a branch of Ecology that has as object of study from the microbiota present in a minimal portion of soil to the highest level of terrestrial ecological organization, the biosphere. Understanding how energy flows from the conversion of solar rays by photosynthetic organisms to the dynamics of decomposition of their matter have been key issues for the Ecology of Ecosystems.