This book displays various topics related to knowledge, preservation and diagnosis of coral ecosystems. It shows different practical case studies, within them, the use of corals as indicators of geochemical thermal anomalies and the use of biochemical and molecular frontier tools to diagnose the coral population. It also analyses several aspects of diversity, ecology and distribution of black coral, as well as addresses the ecological significance of bacteria in the community structure of a coral reef. This book presents studies that may be understood from the septogenesis principles to the study of the interconnection of coral ecosystems with artificial reefs, and a deep review about the methodological instruments supported by the molecular knowledge to make decisions on the coral ecosystems management.