COSAM Professor Publishes Research on Fish Response to Marine Heatwave
A new professor in the Auburn University Department of Biological Sciences is working to understand the responses of marine fishes to climate change and recently had a paper on the subject published in the scientific journal Science Advances.
Moisés A. Bernal joined the Auburn family in August and his paper “Species-specific molecular responses of wild coral reef fishes during a marine heatwave” detailed responses of marine fishes to a marine heatwave in 2016, which greatly affected the fauna of the Great Barrier Reef of Australia.
Originally from Panama, Bernal received his undergraduate degree in biology and environmental sciences from the University of Panama, a Ph.D. in marine science from the University of Texas, Austin, and was a postdoctoral fellow at King Abdullah University of Science and Technology in Saudi Arabia and at the State University of New York at Buffalo.
His research at Auburn focuses on understanding how ocean warming will affect marine fishes, and the mechanisms associated with fast acclimation to elevated temperatures.
The research showcased in the recently published paper was conducted in collaboration with researchers at James Cook University (JCU) in Australia. JCU professor Jodie Rummer, co-author of the publication said extremely warm conditions were forecast for the Great Barrier Reef in 2016 which gave the team the motivation to collect different species throughout the heatwave event.
“Researchers were very interested in understanding the response of multiple marine organisms to the marine heatwave, and we managed to complement these observations with a genetic technique called gene expression” explained Celia Schunter, co-author and assistant professor at the University of Hong Kong.
Five different species of coral reef fishes were collected at the beginning, middle and the end of heatwave to understand their response to the unusual warming.
“The idea was to analyze the expression of as many genes as possible to characterize the stressful response of fishes to the elevate temperature and see if all species were responding in the same way” Bernal said. “In the end we found that the molecular response to warming varies depending on the species and the stage of the heatwave, as we observed differences between three weeks of sampling.”
Bernal is one of the lead authors on the paper and led the molecular portion of the research along with collaborators in Hong Kong, Japan and Saudi Arabia.
“Most of the analyzed species showed a molecular response that is associated with higher metabolic demands, which is similar to what happens to an athlete doing intense exercise” he said. “When water temperature increases, fishes have a higher demand for energy and oxygen, which leaves a signal that is measurable with genetic techniques. This higher energy demand at warming can affect their reproduction, swimming and many other activities, and that is why it is important to understand their response.”
Using molecular approaches to analyze fish livers, this study showed that one of the species was not affected by the increasing temperatures.
“That tells you that not all species are responding the same way to climate change,” explained Timothy Ravasi, co-author from the Okinawa Institute of Science and Technology. “Some species are going to tolerate some warming, while other species are going to be very sensitive to changes in temperature, and it is challenging to predict how each species will respond, so more studies of this kind are needed.”
Bernal said he believes this research is unique because usually researchers sample one species of fish at just one time-point, but this team sampled five different species of fishes throughout several months.
“This study provides a more complete picture of what happens to marine fishes in the wild during a marine heatwave,” he said. “However, there are still many questions to explore regarding how fishes will respond to a changing planet.”
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