Seawater carbonate chemistry and reef fish metabolic performance

• Main Authors: Laubenstein, Taryn D, Jarrold, Michael, Rummer, Jodie L, Munday, Philip L
• Format: Dataset
• Language: English
• Published: PANGAEA 2020
• Subjects: Acanthochromis polyacanthus; Aerobic scope of oxygen; Alkalinity; total; standard deviation; Animalia; Aragonite saturation state; Bicarbonate ion; Bramble_reef; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Calculated using seacarb after Orr et al. (2018); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chordata; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); EXP; Experiment; Factorial aerobic scope; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Fugacity of carbon dioxide in seawater; Identification; Laboratory experiment; Mass; Nekton; OA-ICC; Ocean Acidification International Coordination Centre; Other; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.925216; https://doi.org/10.1594/PANGAEA.925216

Elevated CO2 levels have been shown to affect metabolic performance in some coral reef fishes. However, all studies to date have employed stable elevated CO2 levels, whereas reef habitats can experience substantial diel fluctuations in pCO2 ranging from +-50 to 600 μatm around the mean, fluctuations that are predicted to increase in magnitude by the end of the century. Additionally, past studies have often investigated the effect of elevated CO2 in isolation, despite the fact that ocean temperatures will increase in tandem with CO2 levels. Here, we tested the effects of stable (1000 μatm) versus diel-cycling (1000 +- 500 μatm) elevated CO2 conditions and elevated temperature (+2 °C) on metabolic traits of juvenile spiny damselfish, Acanthochromis polyacanthus. Resting oxygen uptake rates (ṀO2) were higher in fish exposed to stable elevated CO2 conditions when compared to fish from stable control conditions, but were restored to control levels under diel CO2 fluctuations. However, the benefits of diel CO2 fluctuations were diminished at elevated temperature. Factorial aerobic scope showed a similar pattern, but neither maximal ṀO2 nor absolute aerobic scope was affected by CO2 or temperature. Our results suggest that diel CO2 cycles can ameliorate the increased metabolic cost associated with elevated CO2, but elevated temperature diminishes the benefits of diel CO2 cycles. Thus, previous studies may have misestimated the effect of ocean acidification on the metabolic performance of reef fishes by not accounting for environmental CO2 fluctuations. Our findings provide novel insights into the interacting effects of diel CO2 fluctuations and temperature on the metabolic performance of reef fishes.