You’re sitting at home scrolling through your phone when up pops a notification from your favorite social media app. “You have a new suggested friend!” But wait, how did this social media app know to suggest this friend to you? The answer: networks—it’s all about who you know, who your friends know, and so on.

The truth is that networks have been used by scientists for decades for understanding social ties, traffic patterns, and brain chemistry. Well, it’s even true for microbiomes: the collections of microorganisms (bacteria, fungi, archaea, and viruses) that live in, on, and around us.

For example, scientists estimate that soils contain 1 billion microorganisms per gram, which could represent more than a million species. And within these webs of diversity are potentially trillions of interactions. But why should you care about these microscopic social networks? Well, it turns out that these relationships are tied to how a microbiome functions. At Berkeley Lab, we are interested in understanding links between plants and their microbiomes as well as between microbes within the microbiome. And his is because plants, just like us, form symbiotic relationships with microbes to help them grow better especially under extreme environmental stress like drought. But how do you survey the microbiome? With their DNA, of course. It tells us who is there, in what abundance, and with whom else.

While we have known for a while that stress could change the diversity of microbes that plants associate with, network science has helped me discover that stress can also completely reorganize the network. In fact, I found that stress not only changes who associates with whom, but also which microbes serve as hubs (which you can think of as the social butterflies—the most highly connected members who function as keystones in the network). I also found that stress led these microbial networks to become more connected, especially among microbes believed to help plants grow better. Most surprising, while we expected stress to increase competition for resources, I actually found that it might promote cooperation and aid in microbiome stability over time. But this is only just the beginning because each microbe in the network has their own story to tell and their own genome filled with information to uncover. Linking these associations to their genomic or metabolomic mechanisms is the next frontier. With this, we would be able to better “suggest” groups of microbes to use in biofertilizers which could allow us to grow plants more easily in a rapidly changing climate. Who knows, maybe we might even call it Facebook of the Field.