Research in the Bartol Marine Biomechanics Lab focuses on the physiological ecology and biomechanics of marine animals, with an emphasis on locomotive and sensory processes. At present Dr. Bartol and his students are using 2D digital particle image velocimetry (DPIV) and 3D defocusing digital particle image velocimetry (DDPIV) to study global flow patterns around swimming squids, cuttlefishes, fishes, and sea turtles. These techniques involve training animals to swim in a water tunnel or viewing chamber seeded with light reflective particles. The particles are illuminated using either a sheet (DPIV) or cylinder (DDPIV) of light produced by two pulsed lasers (see image below). The lasers are synchronized with either a double-shot DPIV or 3-aperture DDPIV video camera, allowing for the collection of a series of "paired" images of the flow around the swimming animals. Using cross-correlation and other particle tracking algorithms, the particle displacements are determined within these paired images, and velocity vector fields are produced. In addition to using these laser-based flow quantification systems, body movements of the animals are recorded during swimming in the water tunnel/viewing chamber using an array of high-speed cameras. This footage is analyzed in conjunction with DPIV/DDPIV data to better understand thrust/lift production, swimming efficiency, turning performance, and escape responses.
Experimental set-up used in DPIV experiments (left) and a video frame of a brief squid Lolliguncula brevis swimming in a field of illuminated particles (right).