The use of co-occurrence patterns to investigate interactions between micro-organismshas provided novel insight into organismal interactions within microbial communities.However, anthropogenic impacts on microbial co-occurrence patterns and ecosystemfunction remain an important gap in our ecological knowledge. In a northern hard-wood forest ecosystem located in Michigan, USA, 20 years of experimentally increasedatmospheric N deposition has reduced forest floor decay and increased soil C storage.This ecosystem-level response occurred concomitantly with compositional changes insaprophytic fungi and bacteria. Here, we investigated the influence of experimental Ndeposition on biotic interactions among forest floor bacterial assemblages by employ-ing phylogenetic and molecular ecological network analysis. When compared to theambient treatment, the forest floor bacterial community under experimental N deposi-tion was less rich, more phylogenetically dispersed and exhibited a more clusteredco-occurrence network topology. Together, our observations reveal the presence ofincreased biotic interactions among saprotrophic bacterial assemblages under futurerates of N deposition. Moreover, they support the hypothesis that nearly two decadesof experimental N deposition can modify the organization of microbial communitiesand provide further insight into why anthropogenic N deposition has reduced decom-position, increased soil C storage and accelerated phenolic DOC production in ourfield experiment.