Respiratory acidosis and O 2 supply capacity do not affect the acute temperature tolerance of rainbow trout ( Oncorhynchus mykiss ).

Autor: Montgomery DW; Biosciences, Stocker Road, University of Exeter, Exeter, EX4 4QD, UK., Finlay J; Biosciences, Stocker Road, University of Exeter, Exeter, EX4 4QD, UK., Simpson SD; Biosciences, Stocker Road, University of Exeter, Exeter, EX4 4QD, UK., Engelhard GH; International Marine Climate Change Centre (iMC3), Centre for Environment, Fisheries & Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT, UK.; School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK., Birchenough SNR; International Marine Climate Change Centre (iMC3), Centre for Environment, Fisheries & Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT, UK., Wilson RW; Biosciences, Stocker Road, University of Exeter, Exeter, EX4 4QD, UK.
Jazyk: angličtina
Zdroj: Conservation physiology [Conserv Physiol] 2024 May 16; Vol. 12 (1), pp. coae026. Date of Electronic Publication: 2024 May 16 (Print Publication: 2024).
DOI: 10.1093/conphys/coae026
Abstrakt: The mechanisms that determine the temperature tolerances of fish are poorly understood, creating barriers to disentangle how additional environmental challenges-such as CO 2 -induced aquatic acidification and fluctuating oxygen availability-may exacerbate vulnerability to a warming climate and extreme heat events. Here, we explored whether two acute exposures (~0.5 hours or ~72 hours) to increased CO 2 impact acute temperature tolerance limits in a freshwater fish, rainbow trout ( Oncorhynchus mykiss ). We separated the potential effects of acute high CO 2 exposure on critical thermal maximum (CT max ), caused via either respiratory acidosis (reduced internal pH) or O 2 supply capacity (aerobic scope), by exposing rainbow trout to ~1 kPa CO 2 (~1% or 10 000 μatm) in combination with normoxia or hyperoxia (~21 or 42 kPa O 2 , respectively). In normoxia, acute exposure to high CO 2 caused a large acidosis in trout (blood pH decreased by 0.43 units), while a combination of hyperoxia and ~1 kPa CO 2 increased the aerobic scope of trout by 28%. Despite large changes in blood pH and aerobic scope between treatments, we observed no impacts on the CT max of trout. Our results suggest that the mechanisms that determine the maximum temperature tolerance of trout are independent of blood acid-base balance or the capacity to deliver O 2 to tissues.
Competing Interests: The authors declare no conflicts of interest.
(© The Author(s) 2024. Published by Oxford University Press and the Society for Experimental Biology.)
Databáze: MEDLINE
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