Table of Contents

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

Collected from the western edge of the Gulf Stream (26°43′93″ N, 79° 59′15″ W) in September 2019, 5–8 km east of West Palm Beach, Florida. All samples were collected during daylight in the upper 15 m. Sampling was done by hand.

Jars with animals and jars with seawater were brought on the deck of a 10 m dive vessel for processing. Within 30 min of divers surfacing, samples were archived or processed as follows. Salps and pteropods were gently poured onto a metal sieve then rinsed with 0.2 μm filtered seawater. Each gut was then removed with dissecting scissors, avoiding as much of the gelatinous tissue as possible. Guts were placed into sterile bead-beating tubes with 0.55 and 0.25 mm sterile glass beads and stored on dry ice until archiving at −80°C in a shore-based laboratory. Salp faecal pellets were sampled from different salp specimens incubated in jars for approximately 1-h after collection. Faecal pellets were collected on a mesh sieve (500 μm), rinsed with 0.2 μm filtered seawater, then stored as above. Jars containing seawater collected near sampled animals were transported on blue ice to the shore-based laboratory. For flow cytometry samples, 2 ml of seawater was fixed at a final concentration of 0.125% TEM grade glutaraldehyde (Tousimis), incubated at room temperature for 10 min, then flash frozen in ethanol cooled with dry ice. Seawater DNA samples were taken by peristaltic pumping onto 0.2 μm membrane filters and were stored on dry ice until archiving at −80°C.

DNA was extracted with the DNeasy Plant Tissue Mini Kit (Qiagen) with the following modifications. Salp guts, salp fecal pellets, and pteropod tissues were ground with a sterile disposable pestle (Axygen, Tewksbury, USA) for 3 minutes prior to extraction. All samples, including seawater, were lysed by bead beating with 0.55 mm and 0.25 mm sterile glass beads at 30 Hz for 2 minutes after addition of lysis buffer, freeze-fractured 3 times, incubated with a final concentration of 2 mg/mL Proteinase K (VWR Chemicals, Solon, OH, USA) for 1 hour at 55 ˚C, and then incubated with a final concentration of 0.9 mg/mL RNase A for 10 minutes at 65˚C. To minimize amplification of eukaryotic host DNA, the primer pair 515F‐Y/806R was chosen to amplify the 16S rRNA V4 hypervariable region. Reactions were performed with 0.5-2 ng of DNA using the QuantaBio 5Prime HotMasterMix (Qiagen Beverly, MA, USA). To overcome PCR inhibition in salp samples, bovine serum albumin (BSA) was added to the salp PCRs, see details below. The Agilent Bioanalyzer High Sensitivity Kit (Agilent Technologies, Waldbronn, Germany) confirmed amplicon size. Triplicate PCRs from each sample were pooled, cleaned with magnetic beads, and paired-end sequenced (2 x 300 bp) with Illumina MiSeq v.3 (Illumina, San Diego, USA). Sequences were deposited in the Sequence Read Archive (SRA).

* Merged biosample and SRA run file
* Removed no data columns from files
* Adjusted parameters to comply with database requirements (spaces, characters, etc)
* Converted date to ISO format
* Split lat/lon column into their own columns

NSF Award Abstract:
The oceans are dominated by microscopic plants and animals (microorganisms) that are at the base of the food web and drive energy and carbon cycles on global scales. Soft jellylike animals called gelatinous grazers specialize in feeding on microorganisms using nets made out of mucus. Gelatinous grazers are abundant in the ocean and have high feeding rates on microorganisms so could have a very strong influence on the abundance and diversity of microorganisms and could change how oceanic food webs are currently understood. However, gelatinous grazers are very fragile and patchy in their distributions so it has been difficult to determine the magnitude and dynamics of these important predator-prey relationships on a meaningful scale using traditional approaches, thus they have typically been disregarded in food web studies. Learning more about the predator-prey relationship between gelatinous grazers and microorganisms will improve understanding of the structure, mechanics, and dynamics of the ocean's food web, which is a critical economic and ecosystem resource on Earth. This project is determining grazing rates by gelatinous animals on microbes to inform food web models. The project also trains students to communicate, disseminate, and interpret scientific findings. These broader impacts goals will be attained through partnerships at the University of Oregon (Applied Scientific Communication) and Portland State University (Advanced Technical Writing), training of 1 PhD student, 2 undergraduates, and 4 science communication interns, and development of a week-long workshop and establish student mentorship relationships towards production of communication products.

The project integrates laboratory and oceanographic approaches to address several specific aspects of the predator-prey relationship between gelatinous grazers and ocean microorganisms. Five distinct types of gelatinous grazers, each with different feeding morphologies and life history, will be studied in an oceanographic setting with an abundant and diverse natural microbial population. These target organisms include pelagic tunicates (salps, appendicularians, doliolods and pyrosomes) and thecosome pteropods. The approach quantifies: 1) grazing rates in the natural ocean environment, 2) particle selectivity with a focus on size and shape and, 3) the morphological and hydrodynamic properties of feeding that underlie the measured grazing rates and particle selection. The project uses a variety of techniques including sampling via SCUBA diving, laboratory experiments, high speed/high resolution videography, flow cytometry, and DNA sequencing techniques.