In this article, we present a case study of an experimental set up of a microalgae-based wastewater treatment prototype in an ecovillage requiring many maintenance operations to function. Taking... Show moreIn this article, we present a case study of an experimental set up of a microalgae-based wastewater treatment prototype in an ecovillage requiring many maintenance operations to function. Taking our cue from maintenance and repair studies, we focus on the embodied engagements by which caring for wastewater unfolds. We examine how aquatic ecologists, environmental engineers and villagers use their senses as instruments of inquiry when handling wastewater, as they observe its colour and smell its occupants, and manually check the connections between tubes and pumps. A multispecies body of microbial wastewater figures prominently, as the metabolism of three species of microalgae dwelling in the wastewater is key to the functioning of the prototype. Turning to insights from multispecies ethnographies of laboratory studies, we expand our focus on embodied engagements across the species barrier while maintenance unfolds. We show how ecologists, engineers and villagers engage in ‘knowing with microalgae’ as the algal community invokes and adapts its metabolism in surprising ways to the interferences stirred by their human caretakers. By juxtaposing three ethnographic stories about knowing (1) with hungry, (2) with stressed, and (3) with dying microalgae, we show how algal bodies are both object and instrument of inquiry. Unexpectedly, they also become, tools of repair, liaising with their human caretakers, with other microorganisms and with added chemicals in the wastewater, as well as natural forces such as heat, sunshine, and frost. Considering the maintenance of and by living matter such as microalgae, we raise questions about life and death as the object of maintenance shifts. In so doing, we urge for a multispecies perspective on maintenance that acknowledges that ‘the inclusion of nonhuman others from the animal/organic world produces a different set of ethical concerns than the engagement with technological entities’ (Puig de la Bellacasa 210, 159). This is needed as societies advance towards ecologically sustainable modes of living in which humans will progressively cohabitate with a wide variety of species as well as the technologies that house and facilitate them. Show less