Scientists describe how Antarctic fishes with and without hemoglobin react to acute thermal stress. The responses may help the fish withstand the impacts of climate change.
Yet dipping below the waves, the Southern Ocean teems with biodiversity: vibrant swaths of sea ice algae and cyanobacteria, swarming krill and crustaceans, bristling kelp forests, gigantic polar sea spiders and sponges, whale pods, and abundant Antarctic fish fauna.
These fishes play a vital role in the Southern Ocean’s food web of 9,000 known marine species, yet their subzero haven may be at risk. A 2021 climate analysis posited that by 2050 some areas of the Antarctic continental shelf will be at least 1 degree Celsius warmer.
Researchers from Virginia Tech’s Fralin Biomedical Research Institute at VTC have published a new study in PLOS ONE describing how two species of Antarctic fish — one with hemoglobin in its blood cells and one without — respond to acute thermal stress.
The research team, directed by Virginia Tech Vice President for Health Sciences and Technology Michael Friedlander, observed that both species responded to progressive warming with an elaborate array of behavioral maneuvers, including fanning and splaying their fins, breathing at the surface, startle-like behavior, and transient bouts of alternating movement and rest.
«Remarkably, our team found that Antarctic fishes compensate for increasing metabolic demands by enhancing respiration through species-specific locomotor and respiratory responses, demonstrating resilience to environmental change and possibly to global warming,» said Friedlander, who is also the Fralin Biomedical Research Institute’s executive director, senior dean for research at the Virginia Tech Carilion School of Medicine, and a professor in the College of Science’s Department of Biological Sciences. «Ambient warming presents a multi-faceted challenge to the fish, including increased temperature of the central nervous system and target tissues such as skeletal and cardiac muscles, but also reduced availability of dissolved oxygen in the water that passes through the gills during respiration. While these findings suggest that Antarctic fishes may be able to behaviorally adapt somewhat under extreme conditions, little is known about the effects of environmental warming on their predation habits, food availability, and fecundity,»
Iskander Ismailov, the study’s first author and a research assistant professor in Friedlander’s laboratory during the study, said, «Behavioral manifestations that we’ve described show that these fishes have powerful physiological capacities to survive environmental changes,» said
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Materials provided by Virginia Tech. Original written by Whitney Slightham. Note: Content may be edited for style and length.