About half of global photosynthesis is carried out by unicellular algae in the oceans. These organisms shape our environment not only by fixing CO2 to organic carbon, but also through the precipitation of minerals. For the last 500 million years, biological mineralization is the driving force for geochemical cycles in the ocean. The mineralization process is intracellular and proceeds under strict biological control, giving rise to spectacular morphologies of the mineral phase. However, the biological mechanisms that control the intricate construction of these minerals are largely unknown.
Elucidating biomineralization processes is challenging, for example: the need to follow unstable, transient, and highly soluble inorganic phases, at the nano-scale, is incompatible with most traditional methodologies. Today, with the rapid development of advanced imaging techniques, optical, electron, and X-ray based, for live or cryo-preserved cells, it is possible to follow such processes with molecular resolution.
We study mineralization processes in two of the most abundant algal groups of modern oceans, diatoms - that form silicified cell wall with nano-patterning unequalled by any man-made system, and coccolithophores - that form calcified scales with unprecedented control over crystal orientation and morphology.