# Ecological, Functional, and Phylogenetic Determinants of Cyanobacterial Biomineralisation

## TL;DR

Cyanobacteria help reduce atmospheric CO2 by forming solid carbonates, a process influenced by their cell structure and environment.

## Contribution

This review highlights the ecological and metabolic factors driving cyanobacterial biomineralisation as an adaptive strategy.

## Key findings

- Cyanobacterial biomineralisation is an underappreciated process in the global carbon cycle.
- Cell wall architecture and metabolic adaptations enable mineral formation in response to environmental changes.
- Ion trafficking across the cell envelope is crucial for carbonate nucleation and growth.

## Abstract

Cyanobacteria play a key role in the biomineralisation of carbon dioxide into solid carbonates, a critical process in the global carbon biogeochemical cycle that links atmospheric CO2 to lithospheric carbonate reservoirs. While photosynthetic carbon fixation by these microorganisms has been extensively studied and is relatively well understood, the biomineralisation pathway remains much less explored, likely leading to an underestimation of its global relevance. This review summarises current findings and highlights the ecological and cellular factors that contribute to cyanobacterial biomineralisation. In particular, the need to cope with fluctuating environmental conditions has played a central role in enabling cyanobacteria to develop rapid metabolic adaptations together with the evolution of a complex cell wall architecture. Within this framework, biomineralisation emerged as a tangible and effective adaptive strategy. Particular attention is given to the metabolic processes and related ion trafficking mechanisms across the cell envelope, which are instrumental in facilitating mineral nucleation and growth.

Cyanobacteria contribute to the global carbon cycle by biomineralising CO2 into solid carbonates. Unlike photosynthesis, biomineralisation is a less‐understood, multifaceted and adaptive metabolic process with significant global impact. It involves cell wall structures, genetic factors, and metabolic pathways that enable mineral formation and help cyanobacteria respond to environmental changes, highlighting the ecological importance of this process.