Marine stromatolites are generated through the interactions of environmental parameters and specific microbial processes. The activities of endolithic bacteria, that bore canals through calcium carbonate (CaCO3) sand grains (ooids) and reprecipitate the CaCO3 as a single layer (i.e. micritic laminae) are especially important in the longer term stability of the stromatolite macrostructure. Image analysis and classification approaches have been used

Microspatial arrangements of sulfate-reducing microorganisms (SRM) in surface microbial mats (~1.5 mm) forming open marine stromatolites were investigated. Previous research revealed three different mat types associated with these stromatolites, each with a unique petrographic signature. Here we focused on comparing "non-lithifying" (Type-1) and "lithifying" (Type-2) mats. Our results revealed three major trends: (1) Molecular typing using the dsrA