CAREER: Geochemical and Biochemical Factors Controlling Skeletal Nucleation and Their Impact on Coral in a Changing Ocean

University Of Washington, Seattle WA

Investigators

Abstract

Nucleation is the first step needed to form calcium carbonate crystals from a seawater solution and represents the building block of coral skeletons. Recently, the pH of the ocean has become more acidic which can impact nucleation, and as such, coral growth. This research will measure nucleation rates under a variety of controlled conditions to identify the important processes controlling skeletal nucleation kinetics, namely environmental, biochemical, or some combination of the two. Additionally, the project will merge science and education in new ways to help improve the diversity in Earth Sciences by increasing the participation of Native American students in oceanography. Partnering with an Anthropology professor at the University of Washington, the scientist will develop a class on how geology and oceanography teaches us about how the oceans have changed over time, how different cultures have adapted to these changes, and consider human?s future on a changing planet. Four undergraduate students taking the class will be eligible for summer internships to participate in the research project. Coral skeletal nucleation is only possible if dissolved ions can overcome an energetic barrier to self-assemble into a calcified structure. The magnitude of this barrier is controlled by the aragonite saturation state and interfacial energy, meaning that nucleation is a product of both geochemical and biochemical controls that are currently not well constrained. Coral paleoproxies have been widely used to study environmental processes through deep time, and therefore, understanding of the initial step, nucleation, should greatly further understanding of the use and applicability of coral paleoproxies. The researcher's group has developed a nucleation assay to measure in vivo nucleation rates. This will be used under a variety of controlled conditions to measure the impact of the biochemical and geochemical controls on nucleation. Under the pressures of changing ocean chemistry due to ocean acidification, it is likely that nucleation rates will be greatly impacted, and it is crucial to begin developing knowledge on the magnitude of the effect ocean acidification will have on coral skeletal nucleation.