Gelatinous zooplankton are a major component of marine planktonic food webs and it has been suggested that they may become increasingly important in the Future Ocean. However, the diet of gelatinous zooplankton and their roles in marine food webs remain poorly investigated, primarily due to methodological challenges. This is particularly true for the marine pelagic tunicate, Dolioletta gegenbauri. This species of doliolid and its relatives including salps, larvaceans, and pyrosomes, at times, form massive blooms in productive ocean continental shelf environments and therefore can have a significant impact on the structure of marine food webs. In this project, we utilized innovative new molecular gut content analysis approaches, and we asked the questions, for the first time, what and how much do doliolids eat? The long-term goal of the project is to understand the ecological role and significance of doliolids in ocean food webs.

Over the course of the 3-year project we completed 25 research cruises in the southern region of the Western North Atlantic, referred to as the South Atlantic Bight continental shelf.  We were able to collect doliolids at each of their life stages, and determine what and how much they ate. These studies revealed that the doliolid diet is considerably more diverse than previously thought, that parasites are common, and that food quality, quantity and parasites are likely all important factors in regulating doliolid population dynamics in continental shelf environments. Perhaps the most surprising finding was that doliolids can be picky eaters. Previously it was thought that because doliolids are passive filter feeders they were not capable of selective feeding.

An important component of this project was a significant effort to train undergraduate and graduate students, K-12 teachers, and to contribute to the development of a more diverse future workforce. Over the course of this project, 3 graduate students at Hampton University (HU) and Savannah State University (SSU) and 2 undergraduate students were trained. Four of the six students were African American women, one was Hispanic and one was a first generation white graduate. Both HU and SSU are Historically Black Colleges and Universities that offer degree programs in Marine Sciences. In addition to students that were directly supported by this project, the project provided significant opportunities for additional graduate and undergraduate students that participated in the research cruises. Eighty K-12 teachers were able to participate in research cruises, and a week-long immersive educators workshop (Rivers to Reefs, https://graysreef.noaa.gov/education/workshops/welcome.html) that was offered each year of the project.

In addition to peer-reviewed publication and conference presentations, a number of educational products were produced including videos. (https://www.youtube.com/watch?v=cgVMDUZO7kg,  https://www.youtube.com/watch?v=zcWPbJXJhjY) , and an article in the magazine Futurum Careers targeted to middle and high school students (https://futurumcareers.com/the-tiny-animal-at-the-centre-of-the-marine-ecosystem). Project data including oceanographic and zooplankton community structure have been archived with the Biological and Chemical Oceanography Data Management Office (BCO-DMO) http://www.bco-dmo.org/project/641283. Diet analysis based on Next Generation Sequencing data has been archived in the Dryad Digital Repository (https://doi.org/10.5061/dryad.99p2308).

Last Modified: 05/23/2019
Modified by: Marc E Frischer