Viruses that infect microbes contribute to climate change by playing a key role in circulating methane, a powerful greenhouse gas, in the environment, according to a new study.

We analyzed nearly 1000 metagenomic datasets

” data-gt-translate-attributes='[{“attribute”:”data-cmtooltip”, “format”:”html”}]’ tabindex = “0” role = “link” style = ” margin: 0px; padding: 0px; border-width: 0px 0px 1px; border-top style: home; border-right style: home; border-bottom style: dotted; border-left-style: start; border-top-color: start; border-right-color: start; border-bottom-color: rgb(0, 0, 0); border-left-color: start ; border-image: start; font: inherit; vertical-align: baseline;”>DNA Researchers found that microbial viruses from 15 different habitats, from different lakes to the inside of a cow’s stomach, carry special genetic elements called accessory metabolic genes (AMGs) to control methane processes. The number of these genes can vary depending on where the organisms live; This shows that the potential impact of viruses on the environment also depends on their habitat.

ZhiPing Zhong, lead author of the study and a research assistant at Ohio State University’s Byrd Center for Polar and Climate Research, said the discovery makes a significant contribution to a better understanding of how methane interacts and moves in different ecosystems.

“It is important to understand how microorganisms drive methane processes,” said Zhong, a microbiologist whose research examines how microbes thrive in various environments. “The microbial contribution to methane metabolism has been studied for decades, but viral studies are still underexplored and we want to learn more.”

The research was published in the journal Nature Communication.

The role of viruses in greenhouse gas emissions

Viruses have helped drive all ecological, biogeochemical and evolutionary processes on Earth, but only relatively recently have scientists begun to explore their connection to climate change. For example, methane is the second largest emitter of greenhouse gases after carbon dioxide, but it is produced primarily by single-celled organisms called archaea.

“Viruses are the most abundant biological entity on Earth,” said Matthew Sullivan, co-author of the study and professor of microbiology at Ohio State’s Center for Microbiome Science. “Here, we expanded what we know about their effects by adding methane cycle genes to the long list of metabolic genes encoded by viruses. Our team sought to answer which part of the ‘microbial metabolism’ viruses actually manipulate during infection.”

While the vital role of microbes in accelerating atmospheric warming is now well known, little is known about how methane metabolism-related genes encoded by the viruses that infect these microbes affect methane production, Zhong said. Solving this mystery took Zhong and his colleagues to spend nearly a decade collecting and analyzing microbial and viral DNA samples from unique microbial reservoirs.

One of the key locations the team chose to investigate was Lake Vrana, part of a nature reserve in Croatia. In methane-rich lake sediment, researchers discovered numerous microbial genes that affect methane production and oxidation. Additionally, they identified diverse viral communities and identified 13 types of AMHs that help regulate the host’s metabolism. Even so, there is no evidence that these viruses directly encode methane metabolism genes themselves, suggesting that the viruses’ potential impact on the methane cycle depends on their habitat, Zhong said.

Livestock farming and environmental impact

Overall, the study found that greater numbers of methane metabolism AMHs were more prevalent in host-associated environments, such as the cow’s stomach, while fewer of these genes were found in habitats such as lake sediments. Since cows and other livestock are also responsible for about 40% of global methane emissions, their work suggests that the complex relationships between viruses, living things, and the environment as a whole may be more complex than scientists once thought.

“These findings suggest that the global impact of viruses has been underestimated and deserves more attention,” Zhong said.

Although it is unclear whether human activities have influenced the evolution of these viruses, the team hopes that the new understanding gained from this study will increase awareness of the viability of infectious agents across all life on Earth. However, Zhong said more experiments are needed to further examine the internal mechanisms of these viruses to better understand their contribution to the Earth’s methane cycle, especially at a time when scientists are working on ways to reduce methane emissions caused by microorganisms.