Beneficial effects of diel CO₂ cycles on reef fish metabolic performance are diminished under elevated temperature

Laubenstein, Taryn D., Jarrold, Michael D., Rummer, Jodie L., and Munday, Philip L. (2020) Beneficial effects of diel CO₂ cycles on reef fish metabolic performance are diminished under elevated temperature. Science of the Total Environment, 735. 139084.

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Abstract

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.

Item ID: 63785
Item Type: Article (Research - C1)
ISSN: 1879-1026
Keywords: Ocean acidification; Oxygen uptake; CO2 cycles; Temperature; Climate change; Reef fish
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Copyright Information: © 2020 Elsevier B.V. All rights reserved.
Additional Information:

A version of this publication was included as Chapter 3 of the following PhD thesis: Laubenstein, Taryn Diane (2019) Relationships between behavioral and physiological performance under elevated CO₂ in marine fishes. PhD thesis, James Cook University, which is available Open Access in ResearchOnline@JCU. Please see the Related URLs for access.

Funders: Australian Research Council (ARC), ARC Centre of Excellence for Coral Reef Studies
Date Deposited: 15 Jul 2020 07:47
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change @ 50%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960305 Ecosystem Adaptation to Climate Change @ 50%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 50%
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