Seawater carbonate chemistry and experiment on pH effects on coralline-epiphyte complex (Ellisolandia elongata)

• Main Authors: Guy-Haim, Tamar, Silverman, Jacob, Wahl, Martin, Aguirre, Julio, Noisette, Fanny, Rilov, Gil
• Format: Dataset
• Language: English
• Published: PANGAEA 2023
• Subjects: Alkalinity; total; standard deviation; Aragonite saturation state; Benthos; Bicarbonate ion; Biomass; ash free dry mass; Bottles or small containers/Aquaria (<20 L); Calcification/Dissolution; Calcification rate; Calcite saturation state; Calculated using CO2calc; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; aquatic; Coast and continental shelf; Distance; Ellisolandia elongata; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Macroalgae; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.960969; https://doi.org/10.1594/PANGAEA.960969

Coralline algae, a major calcifying component of coastal shallow water communities, have been shown to be one of the more vulnerable taxonomic groups to ocean acidification (OA). Under OA, the interaction between corallines and epiphytes was previously described as both positive and negative. We hypothesized that the photosynthetic activity and the complex structure of non-calcifying epiphytic algae that grow on corallines ameliorate the chemical microenvironmental conditions around them, providing protection from OA. Using mesocosm and microsensor experiments, we showed that the widespread coralline Ellisolandia elongata is less susceptible to the detrimental effects of OA when covered with non-calcifying epiphytic algae, and its diffusive boundary layer is thicker than when not covered by epiphytes. By modifying the microenvironmental carbonate chemistry, epiphytes, facilitated by OA, create micro-scale shield (and refuge) with more basic conditions that may allow the persistence of corallines associated with them during acidified conditions. Such ecological refugia could also assist corallines under near-future anthropogenic OA conditions.