| Species within the phylum Ctenophora are an ubiquitous component in the worlds oceans yet the phylum is a relatively unknown group in terms of hydromechanics of locomotion, morphology, taxonomy, distribution, and behavior. This dissertation examines the functional morphology of ctenophores from five of the seven orders within the phylum Ctenophora, and the role that morphological features have with regard to locomotion, feeding, and/or manipulation of water. Behavioral observations from the field and the laboratory are integrated into this study of ctenophore functional morphology. The use of blue-water snorkeling and SCUBA coupled with submersible observations and laboratory studies have facilitated this research. Part of this dissertation represents the first hydromechanical study on ctenophore locomotion that incorporates measurements both in the laboratory and in situ. They suggest that previous hydrodynamic models applied to ctenophore ciliary flow are incomplete, as the models are based on assumptions that are not valid for ctenophores. A preliminary theory ('plate-theory') that is based on whole animal assumptions is presented. When combined with in situ work, the modeling of ctenophores as an additional method of collecting information about these relatively delicate organisms proved to be invaluable. In situ observations with fluorescein dye have enabled the description of the various manners in which ctenophores can move water: 'jet-propulsion', 'fold and flush', 'flying', 'clapping', undulatory, 'squeezing', 'tractor-tread', Helmholtz instability, vortex rings, edge vortices, the effects of various morphologies on the wake and drag, and the typical ciliary propulsion with ctene plates and rows. For the first time, these modes of water manipulation are combined with measurements of Reynolds number, estimates of drag forces, behavioral patterns, and morphology. The description of several new species from the Catalina Bight and from the Monterey Submarine Canyon indicates that ctenophores are still a relatively unknown group. The measurement of in situ swimming velocities, the visualization of flow fields, and the modeling, combined with the analysis of prey capture, handling mechanics, and the mechanics of locomotion have provided a beginning to the study of this phylum whose members inhabit all depths of all the oceans. |
