Award: OCE-1829932

Ctenophores are gelatinous predators found throughout the world's oceans, and their predatory impacts can profoundly affect planktonic communities. A variety of methods employed by marine scientists have converged to demonstrate the key roles these animals play in determining planktonic composition and energy flows in coastal ecosystems. The role of oceanic ctenophores, however, is still sparsely documented. Oceanic ctenophores are characterized by more delicate gelatinous bodies that usually do not survive capture by conventional nets and do not perform naturally when transferred from their wall-less oceanic environment to shipboard bottles and containers. The difficulty in obtaining quantitative measurements on feeding by oceanic species has limited the ability to understand the role of these organisms in oceanic systems. During this study the investigators established a new field site for studying oceanic plankton and developed and refined an in situ brightfield imaging technique that will be applicable to other fragile plankton such as cnidarian siphonophores, pelagic molluscs, marine snow and large protists such as radiolarians. High-resolution videography and imaging methods both in situ and in the laboratory revealed how predator-prey interactions and feeding currents determine ingested prey and show that predatory impact of oceanic species rivals that of coastal species, in spite of a much sparser prey field in the open ocean. The results will enable inclusion of the activities of these widespread and important animals in models of epipelagic food web dynamics. Training of new scientists included postdoctoral, graduate and undergraduates (including two REUs). The research has been disseminated through nine papers in highly regarded scientific journals. Research findings were shared with broader audiences, including high school students, college undergraduates and scientific audiences, through public talks, invited seminars and marine biology courses. Citizen scientists were engaged in the research and provided in situ ctenophore imagery that was incorporated into a published paper. Quantification of trophic impacts by oceanic lobate ctenophores have remained insufficient for incorporation into global material flux models. This study provides modelers with improved estimates for material flux models, which is especially important in light of changing ocean conditions now and into the future. Last Modified: 12/20/2022 Submitted by: Kelly Sutherland