Researchers have recently uncovered a multitude of previously unknown giant viruses in a comprehensive study conducted in oceans worldwide.

The study was led by marine biologist Benjamin Minch and virologist Mohammad Moniruzzaman from the University of Miami. They utilized specialized computer software to analyze the genomes of microbes present in seawater samples, leading to the identification of 230 giant viruses that were previously unidentified.

Understanding these viruses is crucial for gaining insights into ocean life, particularly the survival of marine organisms like protists, which include algae, amoeba, and flagellates.

According to Moniruzzaman, a better comprehension of the diversity and functions of giant viruses in the ocean, as well as their interactions with algae and other microbes, can help predict and manage harmful algal blooms, which pose health risks globally.

Advancements in genome databases, analysis tools, and computer programs have made the process of discovering giant viruses much more accessible, providing scientists with new perspectives on virus transmission and behavior.

For instance, giant viruses are known to contribute to the demise of phytoplankton, essential photosynthetic organisms in marine ecosystems that produce a significant portion of Earth's oxygen. Understanding the viruses that target these organisms could aid in conservation efforts.

In addition to the 230 newly identified giant viruses, the study also unveiled 569 new functional proteins, including nine related to photosynthesis. Some viruses can manipulate their host's photosynthesis processes to obtain energy for survival.

Minch highlighted that giant viruses possess genes associated with cellular functions like carbon metabolism and photosynthesis, typically seen in cellular organisms. This indicates that giant viruses have a significant impact on their host's metabolism during infection and marine biogeochemistry.

The researchers categorized the newly discovered giant viruses into two existing virus orders: Imitervirales and Algavirales. These groups employ distinct infection strategies, with Imitervirales displaying greater genetic complexity, suggesting a more adaptable 'life strategy' that enables the virus to infect a broader range of hosts.

The study underscores that there is still much to learn about ocean life, as each drop of seawater contains numerous viruses. The methods employed in this research hold promise for uncovering more viruses and understanding their role in ocean ecosystems and health.

Minch emphasized that the study lays the groundwork for enhancing tools to detect novel viruses, which could improve monitoring of pollution and pathogens in water bodies.

The findings have been published in Nature npj Viruses.