Project 2
Role of Fins in Propulsion of the Brief Squid Lolliguncula brevis
Although there is considerable diversity in fin form and function in squids, the locomotive role of the fins is not well understood. While the jet is the foundation of the locomotive system for most squids, the fins also play important roles in swimming, providing thrust, lift, and dynamic stability. In this project, several high-speed video cameras were used to record the kinematics of fin motion in the brief squid Lolliguncula brevis, and DPIV was used to study flows around the fins as they undulate/oscillate over a range of swimming speeds.
Some of the key findings of this work are included in the following papers:
Bartol, I.K., P.S. Krueger, J.T. Thompson, and W.J. Stewart. (2008). Swimming dynamics and propulsive efficiency of squids throughout ontogeny. Int. Comp. Biol. 48, 720-733. <pdf>
Stewart, W. J., Bartol, I. K., and Krueger, P. S. (2009). Hydrodynamic fin function of brief squid Lolliguncula brevis. In review.
FUNDING: This research was supported by the National Science Foundation and the Jeffress Memorial Trust.
Project 3
Role of the Carapace and Fins of Boxfishes in Stability and maneuverability
Boxfishes are marine fishes having rigid carapaces that vary significantly among taxa in their shapes and structural ornamentation. Using three separate but interrelated approaches (DPIV, pressure distribution measurements, and force balance measurements), we determined that four species of boxfishes produce vortices around their keels that lead to self-correcting trimming forces during swimming. For example, when a boxfish pitches upward in a turbulent environment, spiral flows develop above the keels and are strongest at the posterior edge of the carapace. The low pressures that result from the vortices pull the back-end of the fish upwards, returning it to a level trajectory. This sophisticated self-correcting systems acts quickly and automatically without neural processing and reduces the complexity of boxfish swimming movements, which saves energy and enhances sensory acuity. Interestingly, systems that are stable are generally not very maneuverable because every change in course is counteracted by the stabilizing mechanism. However, boxfishes are unique because they are both stable and maneuverable! Current work on boxfishes focuses on how fins interact with body-induced flows to enhance maneuverabilty.
Results from our work were recently appiled to the development of
Mercedes-Benz's bionic car. and are being used by Navy to make more efficient underwater robots.
The key findings of this work are described in the following papers:
Bartol, I.K., M.S. Gordon, P.W. Webb, D. Weihs, M. Gharib. (2008). Evidence of self-correcting spiral flows in swimming boxfishes. Bioinsp. Biomim. 3:1-7. <pdf>
Bartol, I.K., M. Gharib, P.W. Webb, D. Weihs, and M.S. Gordon. (2005). Body-induced vortical flows: a common mechanism for self-corrective trimming control in boxfishes J. Exp. Biol. 208: 327-344. <pdf>
Bartol, I.K., M. Gharib, D. Weihs, P.W. Webb, J.R. Hove, and M. S. Gordon. (2003). Hydrodynamic stability of swimming in ostraciid fishes: role of the carapace in the smooth trunkfish Lactophrys triqueter (Teleostei: Ostraciidae). J. Exp. Biol. 206: 725-744. <pdf>
Bartol, I.K., M.S. Gordon, M. Gharib, J. Hove, P.W. Webb, and D. Weihs. (2002). Flow patternsaround the carapaces of rigid-bodied, multi-propulsor boxfishes (Teleostei: Ostraciidae). Int. Comp. Biol. 42: 971-980.
FUNDING: This work was funded by the Office of Naval Research.
Project 4
Application of 3D DDPIV to the Study of Squid and Cuttlefish Swimming
Defocusing digital particle image velocimetry (DDPIV) is a technique that was developed originally in Dr. Mory Gharib's lab at the California Institute of Technology. Recently the technology was licensed to TSI, Inc., which has made significant refinements to the software and hardware. This emerging technology provides instantaneous flow measurements within a 14 x 14 x 10 cm volume of fluid, which permits greater real-time volumetric spatial resolution than is possible with standard or even modified DPIV techniques. DDPIV is currently being used in my lab to better understand locomotive processes in squids and cuttlefishes. The technology promises to provide unprecedented 3-dimensional data on complex flows commonly observed in biological systems, expanding our knowledge of vortex-based force production and coordination.
Project 5
Hearing Capabilities of Loggerhead Sea Turtles (Caretta caretta) throughout Ontogeny: An Integrative Approach involving Behavioral and Electrophysiological Techniques
Collaborators: Dr. Soraya Moein Bartol
Little is currently known about sea turtle auditory systems. For this study, we are using electrophysiological and behavioral techniques to study hearing capabilities of sea turtles throughout ontogeny. All experiments are being conducted at the National Oceanic and Atmospheric Adminstration (NOAA) Fisheries Galveston Laboratory, TX. The data collected for this project will serve as an integral component of future assessment plans that address potential impacts of sound on sea turtles.
FUNDING: This project is funded by the Joint Industry Program of the International Association of Oil and Gas Producers.
