Dataset: Phytoplankton growth and grazing rates from in situ incubated dilution experiments conducted on cruise RR2201 on R/V Roger Revelle from Jan to Feb 2022 in the Argo Basin region off NW Australia

Dilution experiments were conducted during four “cycle” experiments on BLOOFINZ cruise RR2201. For each experiment, seawater was collected from Niskin bottles on early-morning CTD hydrocasts (~02:00 local time) at 6 depths in the euphotic zone. For each depth sampled, a two-treatment dilution experiment (Landry et al., 2008, 2011) was prepared, with one polycarbonate bottle (2.7 L) containing unfiltered seawater (100%) and the second (diluted) bottle consisting of ~33% whole seawater with filtered water from the same depth. Seawater was filtered directly from the Niskin bottles using a peristaltic pump, silicone tubing and an in-line 0.2 µm Suporcap (Pall Acro) filter capsule that had previously been acid washed (3.7% trace-metal grade HCl; Milli-Q and seawater rinses). All bottles were secured in coarse net bags clipped to the line of a drogued, satellite-tracked drifter and incubated in situ for 24 h at the depth of collection. Initial and final samples (250 mL) for FlChla were filtered onto GF/F filters and extracted with 90% acetone in a -20°C freezer for 24 h and analyzed on a Turner Designs model 10 fluorometer. Samples (2.3 L) for HPLC analyses of chlorophyll and carotenoid pigments were concentrated onto GF/F filters under low vacuum pressure, immediately frozen in liquid nitrogen and stored at -80°C. The samples were extracted for 2 h in 100% methanol, disrupted by sonication, clarified by GF/F filtration and analyzed (Agilent Technologies 1200 Series) at the analytical facility of the Institut de la Mer de Villefranche (CNRS-France).