Paper short abstract:

Scientists dive in the Baltic Sea study the environmental repercussions of marine heatwaves with an innovative underwater experiment. In this paper I show how, in scientific practices, marine heatwaves are enacted as a spatial, temporal, and techno-material objects that foretell oceanic futures.

Paper long abstract:

This paper draws on ethnographic observations conducted at a marine zoological station in Southern Finland to detail how marine researchers scuba dive underwater to study the effects of marine heatwaves in the Baltic Sea. The Baltic is described as special or peculiar because of, among others, its low biodiversity and salinity levels, high pollution, and relative average shallow depth (which allows for scientific scuba diving); All characteristics that make it a likely image, a time-machine, of what the rest of the oceans could look like in the future. I approach marine heatwaves in the Baltic as objects able “to apprehend time, to foretell futures: ecological, scientific, political, local, planetary” (Helmreich 2023:xvii). Based on a 100-year-old time series of seawater temperatures, researchers identified increasingly frequent marine heatwaves in the sea surrounding their research station. Crucially, however, the time series did not provide any insights on the environmental repercussions. The scientist-divers had to negotiate work underwater to setup a very innovative – yet quite precarious – in-situ experiment in the Baltic Sea: They designed incubation chambers to be placed at the seafloor. Through common household floor-heating technology, they simulated heatwaves inside these chambers and monitored bio-chemical processes through regular water sampling. During my fieldwork, the skills of scientific diving became entangled with the challenges of building underwater incubation chambers (Muka 2023), and with performing and maintaining an experiment functional-while-submerged (Jue, 2020). Studying marine heatwaves and making them apparent, thus, emerge as a spatial, temporal, and techno-material problem of different scales simultaneously.