Fig. 1: Potential roles of protists in microbialite construction and destruction.
From: The eukaryome of modern microbialites reveals distinct colonization across aquatic ecosystems
Two key components of microbialite formation are 1) changes in the saturation index (alkalinity) due to changes in microbial metabolisms (see refs. 6,66 for details) and, 2) production exopolymeric substances (EPS) that initially bind Ca2+ and then act as nucleation site for carbonates (see refs. 5,6). Once formed, microbial internal fabrics can be altered by grazing, bioturbation and formation of EPS networks by protists (3). Photosynthetic and heterotrophic (bacterivorous) protists sometimes have different impacts on these processes.
