The holobiont concept proposes that the functional organism is the sum of the interactions between a host and its microbiome (i.e., the consortium of microorganisms associated with the host). Department of Biology faculty members Colin Jackson and Ryan Garrick are studying these host-microbiome interactions as part of a recent National Science Foundation award to determine the processes that generate and maintain phylogenetic, genetic, and functional diversity of the freshwater mussel holobiont across multiple geographic scales. Freshwater mussels are a highly imperiled, diverse group of animals that play critical roles in rivers through their filter-feeding activities, and contribute to cycling of nutrients. Although the ecological value of freshwater mussels is widely appreciated, little is known about how factors like the genetic diversity within individual mussel populations, species diversity within mussel communities, or interactions between mussels and their gut microbiomes influence the ecological services they provide, across different environments. Similarly, little is known about how host-microbiome interactions have structured the evolution of both components of the holobiont over time. Dr. Jackson and Garrick’s research, in collaboration with researchers at the University of Alabama, will address these questions. The award, funded through NSF’s Dimensions of Biodiversity program, brings almost $800,000 to the Department of Biology and includes funding for graduate students and a postdoctoral scientist to work with Drs. Jackson and Garrick on the project.