Table of Contents

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

Zooglider was deployed in the western Mediterranean Sea between 20 March and 8 May 2023 as a part of the BioSWOT-Med program (Doglioli et al. 2024). It was initially released off the coast of Majorca, navigated to south of Menorca, then recovered at sea and redeployed in the center of an anticyclonic eddy north of Menorca. The shadowgraph imaging Zoocam on Zooglider was activated for dives 1-8 (Majorca, 30 March), dives 245-314 (south of Menorca, 24 April–3 May), and dives 353-389 (eddy, 4-8 May). Zooglider ascended at ~10 centimeters per second (cm/s) and the Zoocam sampled at 1 Hz throughout ascent, providing an image approximately every 10 cm of vertical travel. The 15 cm light path of the Zoocam is illuminated with a red LED (620-630 nm), imaging 250 milliliters (mL) per frame. Further details are in Ohman et al. (2018).

After flatfielding, Regions of Interest (ROIs) were segmented using a two step Canny edge detector (Ellen 2018, Ohman et al. 2018). ROIs were pre-classified using a Convolutional Neural Network (Ellen and Ohman 2024), then the classification of ROIs manually verified. In this verification process we observed numerous phytoplankton chains whose morphology was familiar, but whose dimensions were much greater than expected. We retrieved a subset of phytoplankton chains whose feret diameter was > 2 millimeters (mm) for closer manual inspection. These ROIs were measured manually with an on-screen digital tool.

Data were tabulated and summary statistics calculated for each phytoplankton group.

- Imported location data from CSV file "962204_v1_ohman_dive_record_zooglider_bioswot.csv", a related dataset from the same project.
- Imported phytoplankton data from original file "Giant_Phytoplankton_Measurements_v1.xlsx" into the BCO-DMO system, removing empty rows and treating "NaN" as missing values (missing values are empty/blank in the final CSV file).
- Joined location data into the phytoplankton table using "Dive_number" (source) matched to "Dive" (target) in half-outer mode, adding "latitude_mid_ascent_75" and "longitude_mid_ascent_75" columns.
- Renamed columns to comply with BCO-DMO naming conventions.
- Combined "Date" and "Time_CET" fields to create "ISO_DateTime_CET" datetime column formatted as %Y-%m-%dT%H:%M:%S (ISO 8601).
- Combined "Date" and "Time_CET" fields (input timezone CET) to create "ISO_DateTime_UTC" datetime column formatted as "%Y-%m-%dT%H:%M:%SZ" (ISO 8601), converted to UTC.
- Removed original "Date" and "Time_CET" columns.
- Applied a typo correction in the Taxon column: "Guindardia" replaced with "Guinardia".
- Saved the final file as "999115_v1_long_phytopl_chain_length_zoogl.csv".

NSF Award Abstract:
Ocean fronts are regions of sharp horizontal discontinuities that can alter phytoplankton growth rates and community composition, zooplankton distributions and grazing activity, and predator foraging success. This study is using Zooglider, an autonomous ocean sampler equipped with a range of sensors and capitalizing on a unique opportunity to investigate frontal gradients and plankton communities in the western Mediterranean Sea. It is timed to coincide with a rapid crossover phase of a new NASA satellite mission. The combination of satellite and field-collected data will provide high resolution of the bio-physical consequences of oceanic frontal processes. The project incorporates training for graduate and undergraduate students as well as public outreach. Results are broadly communicated by partnering with a major public aquarium that serves 450,000 visitors per year, including by exhibiting novel porcelain ‘Zooware’ meant to convey the sensory experience of exploring the ocean’s planktonic fauna.

This project focuses on advancing understanding of frontal processes in the western Mediterranean Sea, at a ‘crossover’ site where NASA’s new Surface Water Ocean Topography (SWOT) satellite is making high-frequency sea surface height measurements using a high-resolution sensor. Measurements from the SWOT satellite are resolving small changes in sea-surface height, making it possible to follow the development and temporal progression of ocean frontal systems. The investigator is assessing the consequences of these frontal systems by testing the hypotheses that 1) zooplankton, marine snow particles, and predators are altered in these ocean frontal regions with a size-dependent or trait-dependent response; 2) particle-grazing zooplankton are more closely associated with layers of marine snow than with layers of living phytoplankton; 3) vertical thin layers of zooplankton are more likely to form in frontal than non-frontal regions; and 4) higher predators such as zooplanktivorous fish and marine mammals are more detectable in frontal regions The project makes use of an autonomous ocean instrument, the Zooglider. It includes a shadowgraph imaging Zoocam for resolving zooplankton and marine snow; a dual frequency Zonar to resolve mesozooplankton and larger sources of acoustic backscatter; and a sensitive hydrophone for recording ambient sounds, especially from marine mammals and fishes. These autonomous measurements are coordinated with complementary measurements from a ship-based sampling program, other autonomous vehicles, and satellite remote sensing.