Award: OCE-1829945

Ctenophores are frequently inconspicuous, apparently inanimate components of many marine planktonicecosystems. However, research on one lobate ctenophore, Mnemiopsis leidyi, has demonstrate that theirslow moving, ciliary-powered body design houses ferocious predatory machinery (Fig. 1) that can lead todomination of plankton communities by ctenophores. However, Mnemiopsis is a coastal species limited tonearshore environments and does not extend into oceanic waters. Instead, it is replaced over the muchlarger oceanic realm by oceanic lobate species (pictured in Fig. 2). But do these oceanic species affect theworld's open oceans similarly to Mnemiopsis in coastal areas? Answers to this question have been elusivebecause the gelatinous bodies of these oceanic species are too fragile to transport and manipulate inlaboratory conditions. As a result, the role and impact of these widespread oceanic lobate species hasremained unassessed. This project approached the problem by reversing the typical research process that limits the range of studyorganisms to species capable of thriving in laboratory environments. Instead of bringing animals into thelaboratory, investigators translated their laboratory imaging techniques to underwater designs so that fragileoceanic species can be studied in their natural environments. This created a range of novel in-situ imagingsystems (example in Fig. 3) for application to these animals as well as potentially other species. The oceanicspecies considered, from both Atlantic and Pacific sites, were found to share hydrodynamic stealth predationstrategies (Figure 4) and capture prey at similar rates to the well-studied coastal relative, Mnemiopsis.Oceanic species often occur together and, while mutually consuming several prey types, each ctenophorespecies possessed traits that allowed it to specialize on different portions of the available prey spectrum.During the research process, new methods and equipment were developed and undergraduate and graduatestudents as well as postdoctoral researchers were trained in these approaches. The results clarify the rolesplayed by these ubiquitous predators and provide a basis for their inclusion into broader models of trophicand material transport in the world?s oceans. Last Modified: 02/12/2024 Submitted by: BradJGemmell