Dataset: Microplankton microscopy and biovolume analysis from Lugol's samples collected in Resurrection Bay, AK from January to March of 2023

Microzooplankton samples were collected at 3 depths (50, 150, and 280 m) by gently draining 250 mL of seawater from the Niskin bottle with a silicon tube to avoid bubbling. Samples were then preserved with acid Lugol’s solution to a final concentration of 5% (Strom et al., 2019). Glass was added to saturate silica and prevent dissolution of diatoms. Samples were gently mixed and 100 mL subsamples were settled onto microscope slides. Diatoms, dinoflagellates, and ciliates were identified to lowest taxonomic classification, enumerated, and imaged under an inverted microscope. Linear length and widths of cells were measured for a subset of 5 cells (or maximum number) per sample per taxon using ImageJ. Biovolume was estimated using the median linear measurements per taxon and biovolume was calculated using the volumetric equations most closely matching the cell shape (Hillebrand et al., 1999). Biovolume was then converted to carbon biomass according to established diatom and protist carbon:volume relationships (Menden-Deuer and Lessard, 2000).

Day-trips aboard the R/V Nanuq conducted approximately biweekly in Resurrection Bay, AK during January to March, 2023.