Ocean Acidification and Direct Interactions Affect Coral, Macroalga, and Sponge Growth in the Florida Keys

Coral reef community composition, function, and resilience have been altered by natural anthropogenic stressors. Future ocean coastal acidification (together termed “acidification”) may exacerbate this degradation. Accurately predicting requires an understanding of not only direct impacts on marine organisms but also indirect effects species interactions that influence composition ecosystem functions. In 28-day experiment, we assessed the effect coral–algal, coral–sponge, algal–sponge interactions. We quantified growth corals (Siderastrea radians), fleshy macroalgae (Dictyota spp.), sponges (Pione lampa) were exposed to local summer ambient (603 μatm) or elevated (1105 pCO2 seawater. These are common hard-bottom communities, including shallow reefs, in Florida Keys. Each individual was maintained isolation paired with another organism. (net calcification) similar across seawater interaction treatments. Fleshy had increased biomass when a sponge lost growing coral. Sponges grew more volumetrically treatment (i.e., under conditions). Although these results limited temporal spatial scales due experimental design, they do lend support hypothesis facilitate shift towards abundance directly benefiting which turn provide dissolved inorganic nitrogen