Recent research from The Ohio State University sheds light on how mutations in marine bacteria impact their ability to sink carbon to the ocean floor, despite the presence of persistent viral threats. These bacteria, crucial in determining whether carbon is cycled or stored in the depths, often find themselves in an evolutionary arms race with phages, according to the team's findings published in Nature Microbiology.
Despite being hunted by viruses, it turns out that the mutated bacteria might actually be doing the environment a favor, potentially giving earthly efforts to combat climate change a microscopic but mighty ally. Examining 13 phage-resistant mutants from the Cellulophaga baltica bacteria, researchers observed two types of mutations: surface-level changes that block phage entry, and less understood metabolic mutations occurring inside the bacteria. Operating under threat, these bacteria developed a "sticky" quality, as noted by Marion Urvoy, a postdoctoral research associate at Ohio State, which did not seem to hinder their role but might enhance it in carbon sinking. "Both metabolic and surface mutations caused the bacteria to get stickier," Urvoy stated, as detailed by an Ohio State University publication.
While all mutations came with a cost, the stickiness associated with surface mutations was highly relevant to the transport of carbon to the ocean floor. The study showed these adaptations not only provide resistance to infections but have the surprising side effect of enhancing the bacteria's ability to contribute to the marine biological pump. Cristina Howard-Varona, a research scientist engaged in the work, noted the potential of this discovery and aims to delve deeper into the dynamics of intracellular resistance.
However, not all effects were beneficial. Mutation-induced changes surfaced, causing a slowdown in growth rates, which might ripple through the microbial ecosystem, Urvoy explained. The surface mutations, while offering broader resistance to multiple phages, seemed to come at a greater cost, resulting in the bacteria growing more slowly overall. This complexity illustrates the delicate balance microorganisms maintain while influencing vast ecological processes. Senior study author Matthew Sullivan, professor at Ohio State, emphasized the importance of understanding these microbial dynamics due to their impact on global climate through carbon cycling.
The importance of this research is underlined by its supporters: the U.S. National Science Foundation, the U.S. Department of Energy, and the Swedish Research Council. Alongside Urvoy, the study's contributors include a diverse team from Ohio State, Oak Ridge National Laboratory, University of Arizona, and Linnaeus University in Sweden, working together to unravel the multifaceted roles that viruses and bacteria play in our marine ecosystems.
