Environmental Impacts: Understanding Sea Turtle Shell Strength and Resilience

Led by: Jeanette Wyneken, Ph.D.
Affiliated Home Campus: Boca Raton
Affiliated Department: Biological Sciences

The research in which the REU student will participate aims to provide a fundamental understanding of sea turtle shell strength, stiffness, and resilience to damage, both among and within species. Currently, the material properties of shells have been reported in relatively few freshwater turtle species and no hard-shelled sea turtle species. Available baseline data on the strength of loggerhead sea turtle shells is derived from the mechanical testing of very few specimens and the information remains in unpublished theses. Our project will provide an in-depth assessment of shell properties for loggerhead, green, hawksbill and Kemp’s ridley sea turtles. The limited previous studies report no baseline data for the latter three species. Studying the shell as a mechanical system allows for understanding multiple shell functions, as a rigid spine, a “flexible box” that aide breathing, and as protective armor. Currently, our study is systematically characterizing the diversity of shell mechanical traits through mechanical testing of shell samples from turtle carcasses. These tests allow for stiffness, strength, and resiliency to be calculated for each sample. By exploring the modes of failure and material properties of shell bone in the lab, we can better understand shell failure due to vessel strikes, potential marine energy device collisions and predatory attacks. Additionally, how strength and resilience differ among species and life stages is context for all tests. The micro-structure of shell samples will be evaluated using micro-computed tomography to better understand the structure-function relationships within the shell. This comparative approach provides fundamental information that is valuable to species management concerns, but also provides new understanding the functional traits arising through the evolution of the turtle shell.