The influence of aspect on the biological colonization of stone in Northern Ireland
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- 作者：Catherine Adamson ; Stephen McCabe ; Patricia A. Warke ; Daniel McAllister ; Bernard J. Smith
- 关键词：Aspect ; Colonization ; Greening ; Sandstone ; Algae
- 刊名：International Biodeterioration and Biodegradation
- 出版年：2013
- 出版时间：October, 2013
- 年：2013
- 卷：84
- 期：Complete
- 页码：357-366
- 全文大小：2503 K
文摘
The rate and type of biological colonization of stone is influenced by a wide array of environmental factors in addition to substrate characteristics. A series of experiments was designed to compare the rate and type of biological colonization of stone at varying locations over a 21-month time period. Exposure trials were set up at nine different sites across Northern Ireland that covered a wide variety of environmental conditions. To determine aspect-related differences in colonization, blocks of Peakmoor sandstone and Portland limestone were placed on the north- and south-facing sides of purpose-designed exposure racks. Colorimetry and visual analysis were carried out on collected samples at increasing time intervals. Results showed significantly different rates of darkening and greening over time between north-facing and south-facing blocks, for both sandstone and limestone. This difference is likely to be representative of the fact that in Northern Ireland's wet climate and northern-latitude position, the north face of a building will receive less direct sunlight. Therefore north-facing blocks, once wet, will remain damp for much longer than blocks on other fa?ades. This slow-drying phenomenon is much more hospitable for biological colonization and continued growth than the hostile environment of rapid wetting and drying cycles experienced on the south face.