Bringing heatwaves into the lab: A low-cost, open-source, and automated system to simulate realistic warming events in an experimental setting

Aquatic ecosystems face increasing threats from heatwaves driven by anthropogenic climate change, necessitating continued research to understand and manage the ecological consequences. Experimental studies are essential for understanding the impacts of heatwaves in aquatic systems; however, traditional experimental methods often fail to capture real-world complexity. Here, we present a method for simulating aquatic heatwaves that match the dynamic nature of real-world heatwave events in an experimental setting. Our method allows researchers to re-create heatwaves that have happened in the past or produce entirely new heatwave scenarios based on future projections. A Raspberry Pi serves as the foundation of our autonomous, customizable temperature control system, leveraging a low-cost and open-source platform for adaptability and accessibility. We demonstrate system functionality for laboratory experiments by first simulating a hypothetical marine heatwave scenario with defined temperature parameters and then replicating a real-world marine heatwave that occurred in the Santa Barbara Channel, California, in 2015. The average difference between desired and observed temperatures was 0.023°C for the basic heatwave simulation and less than 0.001°C for the real-world heatwave simulation, with standard deviations of 0.04°C and 0.01°C, respectively. Our novel method facilitates broader access to high-quality and affordable tools to study extreme climate events. By adopting a more realistic experimental approach, scientists can conduct more informative aquatic heatwaves studies.