Detection of endolithic spatial distribution in marble stone

Area of Science:

• Microbiology
• Geology
• Conservation Science

Background:

• Endolithic microorganisms penetrate stone, contributing to biodeterioration.
• Current studies often focus only on spread and depth, not full spatial impact.
• Understanding microbial 3D distribution is crucial for assessing stone monument damage.

Purpose of the Study:

• To investigate endolithic microorganisms' spatial distribution and volume within marble.
• To assess the impact of these microorganisms on stone conservation.
• To evaluate confocal laser scanning microscopy (CLSM) with double staining for this purpose.

Main Methods:

• Marble rock sample analysis using CLSM with propidium iodide and Concavalin-A/Alexa Fluor 488 double staining.
• Comparison with Scanning Electron Microscopy (SEM), polished cross-sections, thin-sections, and PAS staining.
• Application of image analysis techniques.

Main Results:

• CLSM with double staining clearly revealed endolithic microorganisms (cyanobacteria, fungi) and their extracellular polymeric substance matrix in a 3D architecture within the marble.
• This technique provided detailed spatial distribution and volume quantification.
• Results were consistent with other microscopy and staining methods.

Conclusions:

• CLSM with double staining is a highly effective technique for visualizing endolithic microorganisms and their matrix in stone.
• This method offers valuable insights into the real impact of biodeterioration on stone monuments.
• It is particularly useful for restoration interventions where endolithic growth is suspected.