Seawater carbonate chemistry and percentage cover of macroalgal species at three locations at Vulcano, Italy

• Main Authors: Cornwall, Christopher Edward, Revill, Andrew T, Hall-Spencer, Jason M, Milazzo, Marco, Raven, Robert J, Hurd, Catriona L
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: Acetabularia acetabulum; Alkalinity; total; standard deviation; Aragonite saturation state; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Caulerpa prolifera; Caulerpa racemosa; CO2 vent; Coast and continental shelf; Codium bursa; Community composition and diversity; Coverage; Cystoseira barbarta; Cystoseira brachycarpa; Cystoseira compressa; Cystoseira crinita; Cystoseira foeniculacea; Cystoseira foeniculata; Dictyopteris polypodioides; Dictyota dichotoma; Dilophus fasciola; Entire community; Event label; EXP; Experiment; Field observation; Figure; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.884805; https://doi.org/10.1594/PANGAEA.884805

Beneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3- use (delta 13C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3- and CO2 had greater CO2 use as concentrations increased. These species (and one unable to use HCO3-) increased in abundance with elevated CO2 whereas obligate calcifying species, and non-calcareous macroalgae whose CO2 use did not increase consistently with concentration, declined in abundance. Physiological groupings provide a mechanistic understanding that will aid us in determining which species will benefit from ocean acidification and why.