La conservation du portail de l’église Saint-Trophime à Arles. Étude microbiologique

Laboratoire de Recherche des Monuments Historiques

Abstract

On the sculptures of the west facade of Saint Trophime (Arles-France), a microbiological research of the causes of the decay of stones (marble and limestones), have shown the activity of heterotrophic microflora, bacteria ables to produce organic acides; the microbiological cycle of nitrogen occurs, with formation of nitrates. In the microbiological cycle of sulphur, the occurence of Thiobacillus thioparus give the explanation for the production of sulphate. The great amount of dusts, soots and birds-dropings give the basis of the rotation of sulphur cycle, thus causing mineralisation of organic sulphur.

For the conservation, it is necessary to clean, consolidate, and to treat with biocides.