Biogeochemistry of Earth Materials
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SEBASTIAN MERGELSBERG
ICTAS DOCTORAL SCHOLAR
PH.D. STUDENT
COLLEGE OF SCIENCE
DEPARTMENT OF GEOSCIENCES
VIRGINIA TECH
B.S. GEOLOGY AND BIOLOGY
RENSSELAER POLYTECHNIC INSTITUTE
One aspect of my research is the biomineralization of exoskeletons. By investigating 10 species across the Malacostraca class of animals, we are finding the physical and chemical structure of chitin holds promise as a secondary proxy for reconstructing skeleton reinforcement.
Using high-energy X-ray diffraction and novel Raman spectroscopy technique to enhance resolution, we determined the detailed nanostructures of chitin and the associated calcium carbonate minerals that comprise the cuticles of multiple body parts. Crab cuticles from the order Brachyura (Dungeness and Rock crabs) exhibit elevated crystallinities of the chitin and calcite in the more reinforced structures (such as the claw). In contrast, the cuticle of lobster body parts show a much greater variability of calcium carbonate crystallinity and a very consistent crystallinity of chitin. Calcite and chitin crystallinity exhibit a dependency within a species (body part to body part), but these dependencies can be different between taxa.
Insights from this study suggest high resolution structural analyses hold promise for developing new proxies for the paleo-environment and paleo-ecology of specific Malacostraca animals