Altered brain ion gradients following compensation for elevated CO2 are linked to behavioural alterations in a coral reef fish

Heuer, R.M., Welch, M.J., Rummer, J.L., Munday, P.L., and Grosell, M. (2016) Altered brain ion gradients following compensation for elevated CO2 are linked to behavioural alterations in a coral reef fish. Scientific Reports, 6. 33216. pp. 1-10.

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Neurosensory and behavioural disruptions are some of the most consistently reported responses upon exposure to ocean acidification-relevant CO2 levels, especially in coral reef fishes. The underlying cause of these disruptions is thought to be altered current across the GABAA receptor in neuronal cells due to changes in ion gradients (HCO3− and/or Cl−) that occur in the body following compensation for elevated ambient CO2. Despite these widely-documented behavioural disruptions, the present study is the first to pair a behavioural assay with measurements of relevant intracellular and extracellular acid-base parameters in a coral reef fish exposed to elevated CO2. Spiny damselfish (Acanthochromis polyacanthus) exposed to 1900 μatm CO2 for 4 days exhibited significantly increased intracellular and extracellular HCO3− concentrations and elevated brain pHi compared to control fish, providing evidence of CO2 compensation. As expected, high CO2 exposed damselfish spent significantly more time in a chemical alarm cue (CAC) than control fish, supporting a potential link between behavioural disruption and CO2 compensation. Using HCO3− measurements from the damselfish, the reversal potential for GABAA (EGABA) was calculated, illustrating that biophysical properties of the brain during CO2 compensation could change GABAA receptor function and account for the behavioural disturbances noted during exposure to elevated CO2.

Item ID: 48420
Item Type: Article (Research - C1)
ISSN: 2045-2322
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Funders: National Science Foundation (NSF), University of Miami (UM), ARC Centre of Excellence for Coral Reef Studies
Projects and Grants: NSF DGIE-0951782, UM Koczy Fellowship, NSF IOS 1146695
Date Deposited: 15 May 2017 01:56
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 100%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 100%
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