A combination of multiple stressors reduces the acclimation potential of Atlantic herring larvae. A recent study shows that an increased temperatures and bacterial exposure together impair the larval stress response. The outcomes of the study highlight the high sensitivity of herring early life stages towards multiple climate change-related stressors. The study was published in the journal Science of the Total Environment by scientists from the Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Zoological Institute of Kiel University.
Previous research has mainly investigated the effect of individual stressors, such as ocean warming, on fish larvae. But what happens when several stressors occur simultaneously? A group of researchers led by first author Dr Andrea Franke, a scientist at HIFMB and AWI, has addressed this question. They carried out a controlled laboratory experiment with several groups of herring larvae, each of which was exposed to different temperatures and bacteria. Subsequently, various analyses were used to examine the acclimation potential of the larvae. These include gene expression measurements, i.e. the transcription of RNA molecules (which are the blueprints for protein synthesis), epigenetic response and the analysis of the larval microbiota.
The study shows that the expression of genes is significantly altered by just one stressor alone. This could help to reduce larval cell damage. In contrast, a combination of heatwave and bacterial exposure, impairs this acclimation response at the gene expression level. This could potentially damage the cells of the larvae.
The publication provides valuable evidence that the interactions between various stressors, which are becoming increasingly frequent due to climate change, could have negative consequences for herring larvae. This would be bad news for the already severely decimated herring population in the Western Baltic Sea.
Original publication:
Franke, A., Bayer, T., Clemmesen, C., Wendt, F., Lehmann, A., Roth, O., Schneider, R. F. (2024). Climate challenges for fish larvae: Interactive multi-stressor effects impair acclimation potential of Atlantic herring larvae. Science of The Total Environment, 953. https://doi.org/10.1016/j.scitotenv.2024.175659