UT Study Unveils Viral Role in Ocean Oxygenation
A groundbreaking interdisciplinary study led by the University of Tennessee, Knoxville, and the University of Maryland has revealed a fascinating connection between viral infections and ocean oxygen levels. The research, published in Nature Communications, demonstrates that viral activity in blue-green algae significantly boosts ecosystem productivity and contributes to a concentrated band of oxygen in the water.
"Our planet is a microbial ecosystem, and viruses play a crucial role in this intricate process," explained Steven Wilhelm, the Kenneth and Blaire Mossman Professor in UT's Department of Microbiology and a senior author of the study. "Their activity can be just as vital for growth and production as it is for causing sickness and disease."
Wilhelm was the chief scientist on the National Science Foundation research cruise to the Sargasso Sea, which led to the publication. The team, including four UT faculty members, three students, and collaborators from the Georgia Institute of Technology, Ohio State University, Technion Institute of Technology in Israel, and the University of Maryland, embarked on the journey aboard the research vessel Atlantic Explorer in October 2019.
During the cruise, they conducted around-the-clock RNA sequencing surveys of the microbiology at the Bermuda Atlantic Time-series Study, a long-standing project that has been collecting ocean data for nearly four decades. The study revealed that viral infection of Prochlorococcus, a type of cyanobacteria, releases nutrients that fuel microbial growth, resulting in higher oxygen levels in the water, even tens of meters below the surface.
"Our findings suggest that this oxygen-rich band, which forms several meters below the surface for several months each year, is at least partly driven by viral activity," Wilhelm noted.
The study establishes a direct link between two fundamental concepts in oceanography: the viral shunt, first described by Wilhelm and Curtis Suttle (University of British Columbia) in 1999, and the microbial loop in the ocean's food web. By analyzing extensive data on cellular and viral activity over day-night cycles, including infection status and viral abundance, researchers identified the impact of viral infections on the entire ecosystem.
"Our analysis shows that viral infections enhance the recycling of carbon and nutrients by other microbes, driving productivity and shedding new light on historical trends that indicate a link between viral activity and ecosystem functioning below the surface," said biology Professor Joshua S. Weitz from the University of Maryland.
The lead author of the paper is Naomi Gilbert, who completed her PhD in 2022. Other UT authors, in addition to Wilhelm, include microbiology Professor Alison Buchan and Assistant Professor Gary LeCleir, as well as former UT students Helena Pound (PhD '21) and Shelby Cagle ('21).
The study was funded by a National Science Foundation Collaborative Research grant and supported by the Simons Foundation and other organizations. Wilhelm and Weitz will be sharing more insights about the research on The Conversation, offering a platform for further discussion and exploration of this intriguing topic.
This study highlights the intricate relationship between viruses and the ocean's ecosystem, challenging our understanding of the ocean's biological processes and the role of viral infections in sustaining life beneath the waves.
