Crystallization done by living organisms, termed biomineralization, involves biological control over crystal nucleation, growth, and crystal orientation patterns in the final biomineral. Marine biomineralization mechanisms are only beginning to be understood, are often surprising, and important to understand the evolution of biomineralizers and their interactions with their environments.

In this seminar I will describe one mechanism of crystallization by attachment of amorphous particles [1] to fresh, forming coral skeletons, and their subsequent crystallization into aragonite crystals [2]. Unprecedented crystal orientation patterns as the one displayed here, analyzed and displayed using Polarization-dependent Imaging Contrast (PIC) mapping [3], reveal that the crystals are spherulitic [4], that is, elongated, and radiating from centers or lines. Spherulites fill 3D space [5] at greater speed than any other crystal growth mode [6], thus this is Nature’s 3D printing.

1.  JJ De Yoreo et al., Science  349, (2015) DOI: 10.1126/science.aaa6760

2.  T Mass et al., PNAS 114, (2017) DOI: 10.1073/pnas.1707890114

3.  PUPA Gilbert et al., PNAS 108, (2011) DOI: 10.1073/pnas.1107917108

4.  C-Y Sun et al., ACS Nano 11, (2017) DOI: 10.1021/acsnano.7b00127

5.  L Yang et al., RSC-Nanoscale  3, (2011) DOI: 10.1039/C0NR00697A