Dataset: Chlorophyll a concentrations collected from Project "DaVINCi" incubations in the Gulf of Naples, Italy from April to May 2022

Samples from incubation bottle treatments were collected after gently mixing treatment bags and siphoning water into a bottle used for filtering. Chlorophyll a was measured by filtering triplicate samples of 50-100 milliliters (mL) of water through 25-millimeter (mm) glass fiber filters (GFF, Whatman) using vacuum filtration. Filters were then extracted in 5 mL of 91% ethanol for at least 12 hours in the dark at room temperature in glass test tubes. Following extraction, the relative fluorescence of each sample was read on a Turner Designs handheld fluorometer (model 8000-010) and then acidified with 2 drops of 10% hydrochloric acid and read again on the fluorometer to correct for phaeophytin (Graff & Rynearson, 2011). Chlorophyll a standards purchased from Turner were used to calibrate the fluorometer prior to measurement.