Meeting Abstract
When compared with air, water is a poor respiratory fluid, with a high viscosity and low dissolved oxygen concentration. Therefore, fluid dynamics likely play a large role in natural selection of respiratory morphology of vertebrates that rely on aquatic respiration, shaping the considerable diversity in the microstructures of fish gill tissues. Fish gills consist of long filaments (primary lamellae), which are covered with small folds of tissue (secondary lamellae) that are the main site of gas exchange. These secondary lamellae vary in shape, size, and spacing among species. In this study, I quantify fluid flow through secondary lamellae morphology in benthic species (including sculpins, snailfishes, and goosefish) and pelagic species (tunas, mackerels, and opah). Using a 3D computational model of the secondary lamellae that I have developed in COMSOL Multiphysics, I model the fluid dynamics of the gills of each species based on measurements from scanning electron microscopy. By measuring flow rate through and around the secondary lamellae over a range of pressures, I have identified a hydrodynamic trade-off between percent efficiency and absolute effectiveness of individual lamellae. While pelagic species are optimized for lamellae efficiency, the lamellae of benthic species may be more effective at the same differential pressures. [Supported by NSF BIO PRFB 1523836]
