Data for experimental conditions were collected from the station locations where water and zooplankton were collected. Temperature and salinity were determined using a YSI ProDO2020.

Laboratory experiments were conducted by collecting raw seawater, filtering it through 200µm mesh sieves into 20L carboys, and then dispensing it into experimental jars. Triplicates bottles were used for each treatment. Treatments included whole seawater (control), whole seawater plus copepods (Zooplankton), and the same treatments plus polyunsaturated aldehydes (PUA) additions (Heptadienal, Octadienal, Decadienal, and Mixed PUA). PUA were dissolved in methanol and added to experimental bottles for a final concentration of 21 nM; for the mixed PUA treatment this was 7nM of each type of PUA. In addition, nutrients were added to all experimental bottles in the form of phytoplankton growth media, to ensure that autotroph growth was not limited by available nutrients in the experimental bottles.

Samples for PUA analysis were collected and processed according to the procedures described in Lavrentyev et al. 2015 & Franzé et al. 2018. These samples were then frozen and shipped to Texas for analysis.

All data were processed in Microsoft Excel.