An intertidal life: Combined effects of acidification and winter heatwaves on a coralline alga (Ellisolandia elongata) and its associated invertebrate community

In coastal marine ecosystems coralline algae often create biogenic reefs. These calcareous algal reefs affect their associated invertebrate communities via diurnal oscillations in photosynthesis, respiration and calcification processes. Little is known about how these function they will be affected by climate change. We investigated the winter response of a Mediterranean intertidal reef, Ellissolandia elongata exposed laboratory to reduced pH conditions (i.e. ambient – 0.3, RCP 8.5) together with an extreme heatwave event (+1.4 °C for 15 days). Response variables considered both physiology (calcification photosynthetic rates) community structure invertebrates (at taxonomic functional level). The combination caused Ellisolandia significantly increase activity. high variability that occurred during simulated night time conditions, indicates there not simple, linear relationship between two may indicate it resilient future contrast, fauna were particularly negatively event, which impoverished as opportunistic taxa became dominant. Local increases oxygen driven can buffer microhabitat fronds, thus favouring survival small invertebrates.