Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Curation Notes
  • Problem Description
• Data Files
• Supplemental Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

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.

Raw zooplankton sample metadata (cruise ID, station, date, time, depth interval, and diel period) were recorded at sea during each cruise. Zooplankton taxa used in fecal pellet production experiments were identified to the lowest practical taxonomic level using stereomicroscope images and standard taxonomic references.

Fecal pellet morphometric measurements (length, width, and projected area) were obtained from stereomicroscope images using INFINITY ANALYZE 7 software (Teledyne Technologies, Inc). Pellet volumes were calculated from measured dimensions assuming cylindrical geometry. Individual fecal pellet production rates were calculated by dividing the total number of pellets produced per individual by the incubation duration (hours).

Zooplankton individual biovolume was estimated from measured body dimensions obtained from post-incubation images.

All data were compiled, quality-checked for transcription errors, and formatted into standardized tables for submission. No statistical analyses, model-based flux calculations, or graphical processing are included in the submitted datasets.

- Loaded 997926_v1_fecal_pellet_production_updated.csv as table "fecal_pellet_production", casting all columns as strings on load; set missing value markers to "" and "nd"
- Converted Date column from M/D/YYYY text format to ISO 8601 date format (YYYY-MM-DD), overwriting the original Date column
- Converted Datetime_Start_UTC column from parsed datetime (format %Y-%m-%dT%H:%M, UTC timezone) to output datetime string format %Y-%m-%dT%H:%MZ
- Output as 997926_v2_fecal_pellet_production.csv

** Version 2 **

- Submitter provided corrected fecal pellet production calculations. The original FPP column was replaced with recalculated fecal pellet production values expressed as mg C ind⁻¹ h⁻¹ (accounting for experiment duration). Added a new mgC column containing fecal pellet carbon per experiment, calculated as Sum_FP_um3 × mgC_um3.
- Completed metadata for rows 1 and 3 (time, duration, and experiment information) were added. Min and max depth were adjusted for rows 1, 3, 9, 10, 25, and 43.

NSF Award Abstract:
The purpose of this collaborative project is to advance understanding of the role of marine planktonic animals (or zooplankton) in the biological pump, or transport of carbon from surface to deeper ocean waters. This movement of carbon from surface to deep ocean water can ultimately affect carbon dioxide in the atmosphere, with implications for global climate. Many marine zooplankton, including species of copepods and krill, play a direct role in the biological pump both because they are abundant and because they can migrate from surface waters at night, where they feed, to depths of more than 500 m at night. At the same time, some organisms called flux feeders will remain at depth and do not migrate. Instead, they rely on particles produced by other zooplankton feeding in surface waters. In this project, the investigators are focusing on populations of flux feeders in the deeper ocean waters of the Sargasso Sea. They are leveraging an ongoing long-term research program, conducting field collections using specialized nets and particle traps, as well lab experiments, as a way to understand how these organisms modify the particles around them. This project is supporting a postdoctoral scientist and providing research experiences for undergraduates at two institutions. An education specialist is creating lesson plans for an award-winning Ask-A-Biologist website, designed for public and K-12 audiences. Images of zooplankton will be disseminated to the public and scientific community via EcoTaxa (a web platform devoted to plankton biodiversity, with images and taxonomic annotation) and physical samples will be archived as part of a teaching library.

The oceanic biological carbon pump refers to the export of dissolved and particulate organic carbon to the deep ocean, and it is a significant driver of atmospheric carbon uptake by the oceans. Evidence from long-term research carried out at the Bermuda Atlantic Time-series Study (BATS) site suggests that the spectrum of particles collected by gel-traps below the euphotic zone changes drastically below 150 m, which is attributed to resident populations of zooplankton that feed on vertically migrating zooplankton as well as sinking particles. The goals of this study are to investigate the role of different zooplankton taxa on both particle aggregate formation and in particle transformation, and to compare and characterize the particles generated by the zooplankton communities with those collected by particle traps. The investigators are combining field collections with experiments onboard ship and in environmental chambers. They are collecting samples over two years, with three cruises a year to capture distinct seasons. They are assessing high-resolution vertical distribution of zooplankton in the upper 600 m using Multiple Opening-Closing Net and Environmental Sensing System (MOCNESS) tows during day- and night-time, to distinguish diel vertical migrators from resident populations and to quantify contributions to particulate organic carbon flux via fecal pellet production. On each cruise, sinking particles are being collected using gel trap tubes attached to the particle traps deployed monthly at BATS. In addition, roller tank experiments are determining how individual zooplankton mediate aggregate formation. Particle types and fecal pellets are being characterized using image analysis and DNA-based analysis of microbial communities. Finally, ongoing data collection from the long-term BATS program is providing invaluable environmental context and will ensure results from this study contribute to ongoing community efforts to observe and predict the fate of carbon in our global system.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.