Roller table experiments with Thalassiosira pseudonana, a small centric diatom, were conducted to produce marine snow aggregates in six treatments: Control (pCO2 = 400 ppm), OA (pCO2 = 750 ppm), water accommodated fraction of oil (WAF), OAWAF, diluted chemically enhanced WAF (DCEWAF), and OADCEWAF. Measurements included intracellular photophysiological responses, oil concentrations and polycyclic aromatic hydrocarbons (PAHs), aggregate morphology, transparent exopolymeric particles (TEP), and extracellular polymeric substances (EPS) to investigate if OA will affect the response to oil spill conditions. The experiments were conducted in the dark to eliminate cell replication and photosynthesis and used both stationary and exponential growth phases.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2022) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2024-01-26.