Soil bacteria may not be so isolated after all

The pore surface in soils is generally considered to be uncolonized, dispersed only with isolated cells or colonies of bacteria and archaea. Since microbial processes arguably depend on cell-cell interactions, and thus on cell density per accessible surface or volume, how can nutrient cycling in soil be sustained if microbial cells are indeed so isolated? Here, we question this empty space-concept and show that bacterial and archaeal densities have been underestimated for decades. A shift in our view of how densely soil is colonized may affect how models of microbial processes, including organic matter dynamics, represent microbial actors and could spark debates on microscale processes such as motility or predation. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project ID JMF-1911-4.