Hundreds Of New Giant Viruses Discovered In Global Waters: Study

In a major scientific breakthrough, researchers have discovered hundreds of previously unknown giant viruses in oceans around the world. Led by marine biologist Benjamin Minch and virologist Mohammad Moniruzzaman from the University of Miami, the team used advanced computer software to analyze seawater samples and identify microbial genomes. Among their findings were 230 giant viruses never before documented.

These discoveries are significant because they help scientists better understand ocean ecosystems, especially the role of viruses in the lives of microscopic marine organisms called protists. These include algae, amoeba, and flagellates, which are essential to the ocean's food chain and overall health.

The study, titled "Expansion of the Genomic and Functional Diversity of Global Ocean Giant Viruses," was published on April 21, 2025, in the journal Nature npj Viruses. It reports the discovery of numerous previously unknown giant virus genomes, significantly expanding the existing scientific understanding of viral diversity in the world's oceans. Within these genomes, 530 new functional proteins were characterized, including nine proteins involved in photosynthesis. This indicates that these viruses may be able to manipulate their host and the photosynthesis process during infection.

"By better understanding the diversity and role of giant viruses in the ocean and how they interact with algae and other ocean microbes, we can predict and possibly manage harmful algal blooms, which are human health hazards in Florida as well as all over the world," said Mohammad Moniruzzaman, a co-author of the study and an assistant professor in the Department of Marine Biology and Ecology.  "Giant viruses are often the main cause of death for many phytoplankton, which serve as the base of the food web supporting ocean ecosystems and food sources. The novel functions found in giant viruses could have biotechnological potential, as some of these functions might represent novel enzymes."

Until recently, giant viruses were largely undetected by scientific methods due to limitations in bioinformatic pipelines. The researchers created an innovative tool called BEREN (Bioinformatic tool for Eukaryotic virus Recovery from Environmental metageNomes), designed to identify giant virus genomes within extensive public DNA sequencing datasets.

"We discovered that giant viruses possess genes involved in cellular functions such as carbon metabolism and photosynthesis-traditionally found only in cellular organisms, said Benjamin Minch, the lead author of the study and a doctoral student in the Department of Marine Biology and Ecology at the Rosenstiel School. "This suggests that giant viruses play an outsized role in manipulating their host's metabolism during infection and influencing marine biogeochemistry."

The authors used the University of Miami's Pegasus supercomputer at the Frost Institute for Data Science and Computing (IDSC) to process and assemble large metagenomes-often exceeding a gigabase per library-enabling the reconstruction of hundreds of microbial community libraries.

"This study allowed us to create a framework to improve existing tools for detecting novel viruses that could aid in our ability to monitor pollution and pathogens in our waterways." Minch added.