Improved Climate Records and New Biodesign StrategiesThrough a Mechanistic Understanding of Sub-Micron Heterogeneity in Environmental Materials
EMSL Project ID
48564
Abstract
From the pace of the ice ages to how the carbon cycle has changed through time, much of what we know about earth history and climate dynamics is based on proxies. Recorded as trace element anomalies or as isotopic shifts, proxies are geochemical relationships that connect environmental parameters to the bulk composition of a natural sample. Recent developments in high-resolution imaging, however, have shown that most environmental materials are characterized by small-scale compositional heterogeneity, complicating the traditional interpretation of proxy-based records. To accurately interpret past records, we need to develop a mechanistic understanding of proxy behavior that can explain small-scale heterogeneity, that can link this variability to bulk composition, and that can resolve specific environmental signals from the bulk record.This proposal will harness the rich and newly accessible chemical data encoded in small-scale heterogeneity, developing a set of tools that can probe the mineral growth process and that can use these data to reconstruct past environmental conditions. Focusing specifically on biomineralization, a complex chemical process occurring at the biological-mineral interface during skeletal self-assembly, our research will quantify how protein-mineral interactions control small-scale heterogeneity and skeletal morphology in a single celled organism called foraminifera. To determine the contribution of organic components towards small-scale heterogeneity, we will use a combination of NanoSIMS and atom probe tomography (APT) to map elemental concentrations at the organic-mineral interface. APT is the only appropriate technique for mapping the 3-D distribution of atoms at this scale. Complementing this approach, we will combine foraminiferal culture techniques with high-resolution helium ion microscopy to uncover how organic mineral-interactions control skeletal morphology. Equipped with a newly acquired NanoSIMS, an atom probe, and a helium ion microscope, few institutions other than EMSL have the appropriate combination of expertise and key instruments necessary for measuring small-scale heterogeneity, making this project especially well matched to the unique capabilities of EMSL.
The biomineral target of our study, the CaCO3 skeletons of foraminifera, was specifically chosen because the preserved skeletons from this organism are widely used to develop climate records. By improving the interpretation of chemical signatures in this archive, our research will directly improve the precision and accuracy of climate records, towards a better understanding of earth system dynamics. Collectively, the research detailed in this proposal will lead to a mechanistic understanding of the processes controlling small-scale heterogeneity in environmental materials, with applications in climate science, in geochemistry, and in the design of complex biomimetic materials.
Project Details
Project type
Special Science
Start Date
2014-10-01
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Bonnin E.A., Z. Zhu, J.S. Fehrenbacher, A.D. Russell, B. Honisch, H.J. Spero, and A.C. Gagnon. 2019. "Submicron Sodium Banding in Cultured Planktic Foraminifera Shells." Geochimica et Cosmochimica Acta 253. PNNL-SA-142331. doi:10.1016/j.gca.2019.03.024
Branson O, EAA Bonnin, DE Perea, HJ Spero, Z Zhu, MA Winters, B Honisch, AD Russell, JS Fehrenbacher, and AC Gagnon. 2016. "Nanometer-Scale Chemistry of a Calcite Biomineralization Template: Implications for Skeletal Composition and Nucleation." Proceedings of the National Academy of Sciences of the United States of America 113(46):12934-12939. doi:10.1073/pnas.1522864113
Fehrenbacher JS, AD Russell, CV Davis, AC Gagnon, HJ Spero, JB Cliff, III, Z Zhu, and P Martin. 2017. "Link between light-triggered Mg-banding and chamber formation in the planktic foraminifera Neogloboquadrina dutertrei." Nature Communications 8:Article No. 15441. doi:10.1038/ncomms15441