The ocean transformation due to direct or indirect human interference is a fact. Among the most threatened ecosystems are the so called “animal forests”. Animal forests are considered alive three-dimensional structures mostly (or completely) composed by hexacorals, octocorals, sponges, etc. In tropical seas, symbiotic octocorals (soft corals) are important part of these complex structures. Several synergic effects, acting as stressors in these organisms, have been detected, changing the distribution of species, the partial or total mortality patterns of populations and the associated to this three-dimensional structures biomass and biodiversity. Climate change is the main driver of these stressors, with a clear repercussion in the octocoral population fitness (bleaching events, physiological and metabolic adaptations, decrease in the gonadal output). The photobiology of the species (i.e. symbiont type and concentration, photosynthesis and respiration rates, variation in the photochemical efficiency, etc.) and its effects in front of climate change effects has been studied in hexacorals (hard corals), being the symbiotic octocorals largely neglected. The aim of the project is to understand how futures scenarios of warming temperatures, ocean acidification and food changes will impact the photobiology and physiology of symbiotic octocoral population, reflected in the health status and reproductive capability of this group. Specific objectives of the project are: a) properly describe photo biological features in Caribbean selected symbiotic octocorals; b) Make exsitu experiments with different temperature, acidification and food availability testing metabolic and gonadal output response; c) Make in situ seasonal monitoring of the species biology and environmental factors at different depths to d) Make a model of potential changes in the population distribution and recovery capability after the stress effects.