PhD Oral Defense of Molly Moynihan: From the microbial to the mechanical: environmental impacts on coral nitrogen cycling, microbial communities, and skeletal properties
- Oral Defense
About the Event:
Corals are architects of their own environment that build physical structures forming habitat for diverse organisms, recycle nutrients, host microorganisms, support biodiversity, and provide storm protection to coastal populations. By combining materials science, paleoclimate, biogeochemical and molecular methods, a multi-disciplinary approach was used to study how environmental conditions influence coral properties. Differences in the mechanical properties of coral lattices document large and unexpected variability in the physical properties of coral skeletons, both between regions and over time. These results suggest that environmental conditions can embrittle coral skeletons, ultimately increasing the rate of erosion on reefs. My work also examines the biogeochemical properties of microbial communities in both the coral skeleton and tissue. By designing and conducting in situ experiments to measure nitrogen fixation in corals, I show that skeletons are a significantly overlooked source of fixed nitrogen in coral. These findings improve our understanding of the functional role of coral-associated microbes and their contribution to coral reef biogeochemical cycling. As coral reefs are facing a multitude of threats from both local and global human activities, understanding how corals and the services they provide respond to changing environmental conditions can improve our ability to preserve and protect these ecosystems.
Members of the Oral Examination Panel
- Assoc Prof Janelle Thompson (Chairperson), Nanyang Technological University, Singapore
- Assoc Prof Case Rebecca Josephine (Member), Nanyang Technological University, Singapore
- Asst Prof Patrick Martin (Main Supervisor), Nanyang Technological University, Singapore
- Assoc Prof Ali Gilles Tchnguise Miserez (Co-Supervisor), Nanyang Technological University, Singapore
- Associate Curator Nathalie Goodkin (Mentor), American Museum of Natural History
About the Speaker:
Molly Moynihan received a Bachelor’s degree in Science of Earth Systems from Cornell University (2011) and a Master’s degree in Oceanography from the Université Pierre et Marie Curie (2014). Since 2015, she has been a PhD student at Nanyang Technological University under the supervision of Dr. Nathalie Goodkin and Dr. Patrick Martin. Her research has taken an interdisciplinary approach to coral science, and she has studied questions surrounding both the structural properties of coral skeletons, as well as nutrient cycling within the coral tissue and skeleton. In developing new techniques to study corals in situ and in the laboratory, her work provides novel insight into how both the physical structure of coral skeletons and the nutrient cycling services that corals provide vary under changing environmental conditions.