Unravelling The Mechanisms Of Biomineralization In A Biogeochemically Significant Microbe Through Multimodal Nano-Imaging At The Organic-Inorganic Interface
EMSL Project ID
51109
Abstract
The pace of skeletal growth in shells and bones during biomineralization is impacted by interactions between biologically produced organic compounds and the growing mineral. The organic component within biominerals is small, typically less than 5 % by mass, but crucial. It acts as a scaffold that directs self-assembly of these hierarchical materials. It also acts to control growth rates, crystal habit, and which mineral polymorph nucleates. At a mechanistic level, organic-mineral interactions allow organisms to overcome chemical and physical barriers to crystal growth. Thus, organic-mineral interactions play a major role in defining how calcifying organisms respond to changes in the earth system. For example, they can modulate the response of skeletal growth to more acidic ocean chemistry. Since calcium carbonate formation is a major component of the global carbon cycle, uncovering the organic-mineral interactions that underpin this flux is a key aspect of understanding both modern and future biogeochemical cycling. Furthermore, organic-mineral interactions can alter the chemical composition of a skeleton, impacting reconstruction of the past earth system that rely on trace element proxies preserved in shells and skeletons.To uncover how microbes use organic-mineral interactions to control mineral growth and skeletal composition, we need to develop new tools and systems to: (1) resolve the chemical-scale interactions at the interface and (2) trace the ways that these interactions lead to morphological or compositional features at a larger scale. Our research will uncover how organic-mineral interactions control CaCO3 production in the shell of a single-celled organism (foraminifera). Specifically, we will map the spatial relationship between skeletal organic biomolecules, skeletal composition, and skeletal growth patterns using a correlative imaging approach that combines Infrared-Scanning Near Field Optical Microscope (IR-SNOM) with ToF-SIMS and NanoSIMS. The newly developed rotating frame s-SNOM (R-SNOM) technique is uniquely capable of mapping the sparsely distributed location of protein components within a biomineral, resolving features at the 10s of nm scale. Armed with this technique, we will directly compare the location of organic components with compositional data mapped at a comparable scale using SIMS. This combination of techniques will allow us to spatially link organic components and skeletal features, providing insight into the mechanisms that biomineralizing organisms use to control CaCO3 production. Our research will lead to a mechanistic understanding of the factors controlling a key microbially mediated process in earth system science, the transformation of the critical biogeochemical elements C and Ca into CaCO3 as carbon moves between the atmosphere, ocean, and earth reservoirs.
Project Details
Project type
Exploratory Research
Start Date
2019-11-26
End Date
2022-06-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)