The role of microorganisms in the damage of frescoes of St. Sophia cathedral (Vologda Kremlin)

Researchers have uncovered a significant link between microbial activity and the degradation of frescoes in St. Sophia Cathedral (Vologda Kremlin), part of the UNESCO-listed Ferapontov Monastery ensemble. The study found that bacteria, particularly Bacillus siamensis, and microscopic fungi contribute to the formation of whitish patina on the fresco surfaces by producing secondary calcite—a process also observed in Italian frescoes. Using non-damaging sampling methods and molecular identification, the team demonstrated that these microorganisms accelerate calcite crystallization under specific pH and nutrient conditions, with B. siamensis showing the highest calcifying activity. Scanning electron microscopy confirmed the presence of crystalline structures, suggesting microbial involvement in surface deposits. This discovery provides critical insights into the bio-weathering of cultural heritage sites.

Vlasov, A. D., Zelenskaya, M. S., Vlasov, D. Yu.,. (2025). The role of microorganisms in the damage of frescoes of St. Sophia cathedral (Vologda Kremlin). Èkobioteh, 8(4), 491–505. https://doi.org/10.31163/2618-964x/2025-35