My current research interests examine (1) the role of biotic processes, and human perturbations, in controlling the flow of energy among trophic levels both within and between marine habitats, with emphasis on submerged vegetated habitats, (2) the use of biodindicators in seagrass ecosystems to detect water quality assessment and ecosystem change. Much of the emphasis of the first objective is on experimental assessments of grazing intensity in temperate and tropical seagrass habitats, the responses of temperate and tropical seagrasses to this grazing, the population dynamics of the main herbivores (sea urchins, herbivorous fish, green turtles and dugongs) and the role of the seascape in changing the trophic interactions in marine systems. The second objective is mainly focused on the development of indexes for water quality assessment using bioindicators from the molecule to the ecosystem. The overall significance of this research lies in its attempt to understand the processes that control the distribution and productivity of seagrass dominated habitats. Because of the widespread occurrence of these habitats, the extraordinary productivity and richness of their associated biota and the services they provide, the understanding of the factors controlling their distribution and the effect of human perturbations on those controlling factors is essential to our understanding. Both approaches clearly define good objectives of a better management and conservation.