Short abstract:

The talk focuses on research on bacteriophages (viruses that infect other microbes). I explore how scientists use the image of phages as ‘the dark matter of the biosphere’, and I trace the distinct enactments of ‘nature’ and phages agency across different branches of phage research.

Long abstract:

Since their discovery in the 1910s, bacteriophages have been defined as viruses that interact with other microbial cells, such as bacteria, archaea or other viruses. Such a definition entrenches bacteriophages in their relationality with microbes, and it configures phages’ agency as the capacity to infect microbial cells. However, the past decades of bacteriophage research can be characterised as a process of reconfiguring the scope of phages’ agency. Studies have shown that phages have a fundamental impact on shaping the Earth’s biogeochemical cycles, therefore, phages have been recognised as agents that play a key role in maintaining the conditions that enable life in the biosphere.

Bacteriophages are studied with a range of experimental techniques: bioinformaticians use metagenomic characterisation to map the genomic diversity of phages, while lab-based techniques, such as plaque assays, explore interactions between specific phages and bacterial species. Building on thematic analysis of current scientific literature on bacteriophages, as well as qualitative semi-structured interviews with scientists, I interrogate how bioinformaticians who work with genomic data contrast their work with lab-based methods of studying phages. Drawing on literature on ontological enactment and multiplicity in science and technology studies, I explore how scientists who use different methods to study bacteriophages enact ‘nature’, as well as phages’ agency in distinct ways. I also ask how bioinformaticians and lab-based scientists use the image of phages as ‘the dark matter of the biosphere’ to frame phages’ agency and to draw attention to issues surrounding the detection of phage activity with traditional scientific methods.