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Behavioral Approaches to Studying Innate Stress in Zebrafish
Published on: May 1, 2019
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Acidification alters anxiety-like behaviour and brain gene expression in zebrafish
Jade M Sourisse1, Munisa Tabarova2, Daniele Romeo2
1The Swire Institute of Marine Science, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong; Marine and Environmental Sciences Centre, Laboratório Marítimo da Guia, Faculdade de Ciências, Universidade de Lisboa, Cascais, Portugal.
The Science of the Total Environment
|June 5, 2025
Summary
Freshwater fish show reduced anxiety under future ocean acidification, but brain gene expression changes indicate neurological impacts. Physiological tolerance doesn't prevent behavioral impairment from climate change.
Area of Science:
- Environmental Science
- Aquatic Toxicology
- Neuroscience
Background:
- Freshwater ecosystems face increasing CO2-driven acidification, posing risks to aquatic life.
- Freshwater fish, despite pH tolerance, can experience behavioral and neurological changes due to acidification.
Purpose of the Study:
- To investigate the molecular and behavioral responses of zebrafish (Danio rerio) to elevated CO2 levels.
- To understand the impacts of near-future acidification on fish brain and gill function.
Main Methods:
- Adult zebrafish were exposed to control (~500 μatm) and elevated CO2 (~1000 μatm) for five days.
- Behavioral tests (Open Field, Novel Object Approach) and transcriptomic analysis of brain and gills were performed.
Main Results:
- Elevated CO2 decreased anxiety-like behavior in zebrafish.
- Brain transcriptomics revealed differential gene expression in cytoskeletal organization, cellular transport, immunity, and visual system genes.
- No differential gene expression was observed in gills, but immune and oxidoreduction gene co-expression suggested reduced oxidative stress.
Conclusions:
- Zebrafish exhibit acid-base regulation capacity under predicted end-of-century acidification.
- Despite physiological tolerance, rapid climate change-induced acidification can lead to neurological and behavioral impairments in freshwater fish.
