Solving the Crystal Architecture of Coccoliths Using 4D-STEM.

Marine phytoplankton form functional biominerals with intricate morphologies and architectures. Coccolithophores occupy a special position among these organisms because of their production of intricate calcite scales, called coccoliths. Although coccolith morphologies differ across different species, crystals are organized around an organic matrix systematically to form an arrangement of astounding symmetry. We demonstrate the opportunities emerging from four-dimensional scanning transmission electron microscopy (4D-STEM), to spatially solve the crystallography of such biominerals. Through the development of a computational pipeline, which automatically solves the orientation at image pixels corresponding to crystals, we can map the orientation of the entangled and overlapping crystalline building blocks composing the coccolith. The present work exemplifies how parallel real space and diffraction space recordings can facilitate and improve the throughput of deciphering the complex network of biomineral superstructures.