Crystallization by Particle Attachment: New Paradigm for Predicting Influences of Environmental Change on Calcification Processes

Traditional approaches to interpreting the formation of marine biominerals were founded on the classical models of crystal growth that were based on observations of mineral systems with high solubility. In these systems growth is dominated by attachment of individual ions to step edges. As Earth scientists began to use high-resolution and in situ TEM methods to investigate the growth of biological minerals and sparingly soluble synthetic materials, the importance of nanoparticle assembly became important. These studies show that the formation of many biominerals cannot be explained solely by the monomer-by-monomer addition of classical models. Rather, the process begins by forming particles that can begin as small molecules, clusters, droplets, or nanocrystals. The particles subsequently interact to give rise to crystalline structures. Evidence from biological and synthetic studies shows crystallization by particle attachment (CPA) processes are widespread (De Yoreo et al., 2015, Science), and possibly a prevailing type of crystal growth.

This presentation will outline the dominant pathways for CPA and show evidence for how carbonate mineralization occurs by this process. The revised picture of biominerals is based in evidence from natural and experimental samples and rooted in thermodynamic and kinetic principles. While there is much to be learned about the nature of particle-particle interactions, CPA offers a process-based construct for deciphering chemical signatures and predicting how changing environmental conditions will influence calcification.