Seawater carbonate chemistry and photosystem II (PSII) function, bleaching of coralline alga Amphiroa gracilis and larval settlement ofthe sea urchin Heliocidaris erythrogramma

• Main Authors: Huggett, Megan J, McMahon, Kathryn, Bernasconi, Rachele
• Format: Dataset
• Language: English
• Published: PANGAEA 2023
• Subjects: Alkalinity; total; standard error; Amphiroa gracilis; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chao 1 richness; standard deviation; Coast and continental shelf; Community composition and diversity; Echinodermata; Entire community; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Heliocidaris erythrogramma; Identification; Indian Ocean; Laboratory experiment; Light saturation; Macroalgae; Maximal electron transport rate; relative; Metamorphosed; larvae; Mindarie_Keys; OA-ICC; Ocean Acidification International Coordination Centre; Operational taxonomic unit; Indian; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.958998; https://doi.org/10.1594/PANGAEA.958998

Coralline algae are a crucial component of reef systems, stabilising reef substrate, providing habitat and contributing to accretion. Coralline algae and their surface microbial biofilms are also important as settlement cues for marine invertebrates, yet few studies address the impact of future environmental conditions on interactions between coralline algae, reef microbes and settlement by larvae of marine invertebrates. We exposed the temperate coralline algal species Amphiroa gracilis to warming and/or acidification scenarios for 21 days. Algae became bleached but photosystem II (PSII) function was not measurably impacted. Settlement by larvae of the sea urchin Heliocidaris erythrogramma was reduced and the structure of the prokaryotic community associated with A. gracilis was altered. Coralline algae in ambient conditions were dominated by Alphaproteobacteria from the Rhodobacteraceae including Loktonella; those under warming were dominated by Bacteroidetes and Verrucomicrobia; acidification resulted in less Loktonella and more Planctomycetes; and a combination of warming and acidification caused increases in Bacteroidetes, Verrucomicrobia and the Alphaproteobacteria family Hyphomonadaceae. These experiments indicate that predicted future environmental change may reduce the ability of some temperate reef coralline algae and associated reef microbes to facilitate settlement of invertebrate larvae as well as having a direct impact to algae via bleaching.