Viruses influence methane production across various ecosystems

We live in a world where even the smallest organisms hold the power to shape the climate. Scientists from The Ohio State University have discovered that viruses play a critical role around us – not by causing diseases, but by influencing the metabolism of microbes that produce methane, a potent greenhouse gas. 

Microorganisms drive methane production

In places like marshes, rice paddies, and animal digestive systems, where there’s little to no oxygen, microscopic creatures called archaea break down organic materials. This breakdown process, called methanogenesis, creates methane gas, which is a powerful greenhouse gas. 

“It’s important to understand how microorganisms drive methane processes,” said study lead author Dr. Zhi-Ping Zhong, a microbiologist at The Ohio State University. “Microbial contributions to methane metabolic processes have been studied for decades, but research into the viral field is still largely under-investigated and we want to learn more.”

Methane contributes to global warming

Methane traps heat in Earth’s atmosphere, contributing significantly to global warming. Compared to carbon dioxide (CO2), each individual methane molecule is much better at absorbing heat, making it a major player in the greenhouse effect. 

While it stays in the atmosphere for less time than CO2, methane’s potent heat-trapping ability in the short term leads to faster increases in global temperatures. This effect intensifies climate change by raising Earth’s surface temperature, changing weather patterns, melting ice caps, and increasing sea levels. 

Metagenomes examination

The scientists examined nearly 1,000 sets of genetic data, called metagenomes, collected from diverse locations like the ocean and animal digestive systems. These datasets were analyzed for the presence of specific viral genes that could potentially affect methane-related processes in the microbes they infect. 

By identifying and recording these genes, called auxiliary metabolic genes, the researchers aimed to understand how viruses might influence methane production and consumption across different ecosystems. 

Viruses and methane production

The study revealed 24 unique viral genes potentially involved in 25 different reactions related to methane production and consumption. Interestingly, the distribution of these methane-related genes varied significantly. 

Viruses living inside animals, like those in the stomachs of cows, had more of these genes compared to viruses in general environmental settings like water or sediment. Overall, 16 out of the 24 identified genes were found in cows’ stomachs, while far fewer were found in marine water, marine sediment, lake water, and hot spring sediment.

Novel viruses revealed in Croatia

The researchers also studied a lake in Croatia and found a surprising novel variety of viruses living in the bottom sediment, where there’s a lot of methane gas. This suggests that there are many more viruses in these environments than we previously knew, and they might be playing a role in how much methane is produced or broken down. 

These viruses contain unique genes and abilities that haven’t been seen in other viruses before. It’s like finding a whole new group of creatures in an ecosystem – they might be doing things we never even imagined, and their presence could be important for how the whole system works.

Broader implications

“These findings suggest that global impacts from viruses are underestimated, and deserve more attention,” said Dr. Zhong.

Additionally, the study highlights a need for research on how viruses influence the way microbes function, as this area is not well-understood. “This work is a beginning step for grasping the viral impacts of climate change,” noted Dr Zhong. “We still have lots more to learn.”

The study is published in the journal Nature Communications.

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