In a perspective of sustainable management, the balance between ecological dynamics, social and economic are now at the heart of ecological modeling and environmental strategies screenwriting. Diversity and marine ecosystems function illustrates biodiversity, habitat diversity, structures and food webs in various oceans of the world and systems: pelagic and benthic ecosystems, coral reefs and seagrass beds, oasis of hydrothermal vents ridges or areas rich upwelling. Appropriate observation methods, long-term monitoring and modeling reveal the complexity of systems, trophic interactions and spatiotemporal dynamics. The ecosystem approach is a prerequisite to assess the state of these systems, their living resources and ecological services involved in local and global environmental changes.