Dataset: Quantification of zooplankton fecal-pellet production by on-board incubation experiments during seven Bermuda Atlantic Time-series Study (BATS) cruises aboard the R/V Atlantic Explorer from Jul 2021 to Mar 2023

Zooplankton Collection

Zooplankton were collected during six Bermuda Atlantic Time-series Study (BATS) cruises between July 2021 and March 2023 aboard the R/V Atlantic Explorer. Sampling was conducted using a 1-m² Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) equipped with 150-µm mesh nets, Scripps Institution of Oceanography electronics, and strobe lights to enhance capture of fast-swimming taxa. Tows were performed during both day and night from the surface to 600 m, with a focus on the upper 300 m.

Fecal Pellet Production Experiments

Target zooplankton taxa were collected using MOCNESS tows and incubated individually in 1-L acid-washed plastic containers ("Copepotties") filled with 0.2-µm filtered seawater. Each container included an inner insert constructed from a 1-mm mesh-bottomed plastic cup to allow separation of fecal pellets from the zooplankton. Incubations were conducted in the dark at approximately 20°C for 8–12 hours during both day and night periods.

Following incubation, fecal pellets were collected under a dissection microscope using glass pipettes and rinsed three times with nuclease-free water. Pellets were imaged under a stereomicroscope, and morphometric measurements were obtained using INFINITY ANALYZE 7 software (Teledyne Technologies, Inc). Fecal pellet areas measured from images were converted to biovolumes (µm³) using shape-specific geometric formulas applied to different particle categories (e.g., spherical for fecal and phytodetrital aggregates, cylindrical for euphausiid pellets). Biovolumes were then converted to carbon content (mg C) using empirically derived conversion factors from published oceanographic studies (Alldredge & Gotschalk, 1990; Silver & Bruland, 1981; Durkin et al., 2021). Zooplankton individuals responsible for pellet production were imaged separately after incubation to confirm taxonomic identity and to measure body dimensions, which were used to estimate individual biovolume and biomass.