Transcriptomic insights into the antagonistic responses of Antarctic marbled rockcod, Notothenia rossii, to elevated temperature and acidification.

The escalating impacts of climate change, particularly ocean acidification and warming, are pivotal stressors for marine ecosystems and have profound effects on biota in polar regions. This study investigated the immunological responses of the Antarctic fish Notothenia rossii to environmental stressors indicative of future ocean conditions under the Intergovernmental Panel on Climate Change Shared Socioeconomic Pathways 5-8.5 scenario for 2100. We exposed N. rossii to conditions simulating present-day conditions: control, elevated temperature, acidification, and both stressors combined over six days. Utilizing RNA-Seq for comprehensive gene expression analysis, we identified significant upregulation and downregulation of immune-related pathways, highlighting a complex interplay of genes involved in complement and coagulation cascades, the intestinal immune network for immunoglobulin A production, cytosolic DNA sensing, natural killer cell-mediated cytotoxicity, and Interleukin 17 signaling pathways. Our findings revealed a predominantly antagonistic gene expression response, suggesting an intricate balance between energy allocation for maintaining homeostasis and the capacity of the immune system to combat stressors. This reflects a potential adaptive mechanism to combined environmental stressors, underscoring the complexity of immune responses in N. rossii and suggesting both potential vulnerabilities and resilience in the face of climate change. This study provides critical insights into the immunological impacts of acidification and warming on Antarctic marine species, emphasizing the need for further research to unravel the mechanisms underlying these observed changes and inform conservation strategies for polar ecosystems in a changing global climate.