Abstract：
Although ceramic objects are an important part of the worldwide cultural heritage, few investigations on the effects of lithobiontic growth on their outdoor conservation are available in the literature. Many aspects of the interaction between lithobionts and stones are still unknown or strongly debated, as in the case of equilibria between biodeterioration and bioprotection. This paper describes research on the colonization by lithobionts on outdoor ceramic Roman dolia and contemporary sculptures of the International Museum of Ceramics, Faenza (Italy). Accordingly, the study i) characterized the mineralogical composition and petrographic structure of the artworks, ii) performed porosimetric measurements, iii) identified lichen and microbial diversity, iv) elucidated the interaction of the lithobionts with the substrates. Moreover, v) the measurements of variability in stone surface hardness and in water absorption of colonized and uncolonized areas were collected to assess damaging and/or protective effects by the lithobionts. The investigation showed how the biological colonization depends on physical properties of the substrates as well on climatic conditions of environments in which the ceramic artworks are located. The results indicated that lichens Protoparmeliopsis muralis and Lecanora campestris may have a bioprotective effect on ceramics with high total porosity and pores with very small diameters, as they poorly penetrate the substrate, do not negatively affect surface hardness and are able to reduce the amount of absorbed water limiting the water ingress. By contrast, Verrucaria nigrescens, here widely found in association with rock-dwelling fungi, deeply penetrate terracotta causing substrate disaggregation, with negative consequences on surface hardness and water absorption. Accordingly, a careful evaluation of the negative and positive effects of lichens must be carried out before deciding their removal. Regarding biofilms, their barrier efficacy is related to their thickness and composition. Even if thin, they can impact negatively on substrates enhancing the water absorption in comparison to uncolonized parts.
摘要：
尽管陶瓷物品是世界文化遗产的重要组成部分，在文献中，很少有关于岩石生长对其户外保护的影响的研究。长石和石头之间相互作用的许多方面仍然未知或激烈争论，如在生物变质和生物保护之间的平衡的情况下。本文介绍了石质离子在户外陶瓷罗马杜利亚和国际陶瓷博物馆当代雕塑上的定殖研究，法恩扎（意大利）。因此，研究i)描述了艺术品的矿物学组成和岩相结构，ii)进行孔隙率测量，iii)确定地衣和微生物多样性，iv）阐明了岩屑与底物的相互作用。此外，v）收集石材表面硬度和定殖和未定殖区域的吸水率的变异性测量值，以评估石离子的破坏和/或保护作用。研究表明，生物定植如何取决于基材的物理性质以及陶瓷艺术品所在环境的气候条件。结果表明，地衣原虫和Lecanoracampestris可能对具有高总孔和直径很小的孔的陶瓷具有生物保护作用。因为它们很难穿透基质，不会对表面硬度产生负面影响，并且能够减少限制水进入的吸收水量。相比之下,黑疣，在这里广泛发现与岩石居住真菌有关，深深地渗透了兵马俑，导致底物分解，对表面硬度和吸水性有负面影响。因此，在决定移除地衣之前，必须仔细评估地衣的负面和正面影响。关于生物膜，它们的屏障功效与它们的厚度和组成有关。即使薄，与未定殖的部分相比，它们可以对基材产生负面影响，从而增强吸水性。
