What we know and what we need to know about Antarctic marine viruses

Though our understanding of Antarctic marine viruses has come a long way thanks to recent scientific advances, there is still much to be learned to form a complete picture, especially in light of continued climate change

The Antarctic is a harsh and unforgiving climate for many, though there is no shortage of important biological activity happening in the frigid temperatures. Antarctic marine viruses, while proven to be important players in the ecosystem, are not completely understood. Here, researchers aim to fill in the gap between what is known and what is unknown, with a primary focus on RNA viruses, the influence of climate change and what the implications might mean for the rest of the world.

Results were published in Ocean-Land-Atmosphere Research in July 2025.

The synthesis of recent information regarding Antarctic marine viruses has led researchers to determine where more focus needs to be placed to bolster our knowledge on the ecological importance of these viruses.

“Antarctic marine viruses are central players in polar ecosystems, driving microbial mortality, nutrient regeneration, and biogeochemical cycling. Yet, our understanding is still incomplete—especially regarding RNA viruses and their role during phytoplankton blooms,” said Chuan Zhai, researcher and first author of the study.

RNA viruses have been pinpointed to be important contributors to the community of Antarctic oceans, despite there being little available knowledge on them compared to other viruses, such as those in the Caudovirales family. Some RNA viruses appear to align with the seasonal peaks of phytoplankton blooms, suggesting these types of viruses could be crucial to maintaining the food web in Antarctic oceans, as well as contributing to the overall global carbon cycle.

The viruses are also key players in nutrient regeneration. When a virus infects a host, there comes a time when the host cell will rupture (or lyse) and its contents, like newly formed viruses and cellular components, are released into the environment in a process called viral lysis. This process introduces nutrients like carbon and iron into the water, which helps to maintain the ever-important microbial population, setting the stage for the rest of the food web. Viruses might also enhance their host’s survival in the harsh and extreme conditions of the Antarctic thanks to auxiliary metabolic genes (AMGs).

Though this information is integral to the base knowledge of Antarctic marine viruses, more information is always preferred. Work towards determining the diversity and abundance of viruses in the Southern Ocean could open many more avenues to work towards a more holistic view of the ocean and its viral inhabitants. Researchers believe viral tagging (employing the use of fluorescence to label viruses) and single-cell RNA sequencing can help identify the viral hosts. Another aspect of utmost importance is studying the marginal ice zone (MIZ), an area with steep gradients in the chemical composition of the water and high productivity that shifts seasonally.

“The next step is to expand research on RNA viruses and virus–host interactions in underexplored regions of the Southern Ocean, using approaches such as large-scale metatranscriptomics and single-cell sequencing,” said Dr. Fraser Kennedy, researcher and corresponding author of the study.

Additionally, researchers hope to use the expanded research and predictive climate modeling to gain insight into the effects climate change might have on Antarctic marine viruses and how it can impact the global carbon cycle. It is already suggested that temperature shifts and the extent of sea ice will impact the dynamics of host-virus interactions and influence the balance of viruses in the Southern Ocean, and filling in these blind spots of knowledge will most likely prove to be an essential piece of the puzzle for addressing the likely change in Antarctic marine ecosystems as the climate continues to warm.

Chuan Zhai, Fraser Kennedy and Andrew McMinn of the Institute for Marine and Antarctic Studies at the University of Tasmania and The Australian Centre for Excellence in Antarctic Science at the University of Tasmania, Yantao Liang, Min Wang and Andrew McMinn of the College of Marine Life Sciences at the Institute of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Lab of Polar Oceanography and Global Ocean Change at the Ocean University of China, with Yantao Liang and Min Wang of the UMT-OUC Joint Centre for Marine Studies and Min Wang also of the Haide College at the Ocean University of China and The Affiliated Hospital of Qingdao University contributed to this research.

The Australian Research Council Special Research Initiative and the Australian Centre for Excellence in Antarctic Science made this research possible.