Editing Weathering (section)

===Biomechanical relationship===
Living organisms may contribute to mechanical weathering, as well as chemical weathering (see [[#Biological weathering|§ Biological weathering]] below). [[Lichen]]s and [[moss]]es grow on essentially bare rock surfaces and create a more humid chemical microenvironment. The attachment of these organisms to the rock surface enhances physical as well as chemical breakdown of the surface microlayer of the rock. Lichens have been observed to pry mineral grains loose from bare shale with their [[hyphae]] (rootlike attachment structures), a process described as ''plucking'', {{sfn|Blatt|Middleton|Murray|1980|p=249}} and to pull the fragments into their body, where the fragments then undergo a process of chemical weathering not unlike digestion.<ref>{{cite journal |last1=Fry |first1=E. Jennie |title=The Mechanical Action of Crustaceous Lichens on Substrata of Shale, Schist, Gneiss, Limestone, and Obsidian |journal=Annals of Botany |date=July 1927 |volume=os-41 |issue=3 |pages=437–460 |doi=10.1093/oxfordjournals.aob.a090084}}</ref> On a larger scale, seedlings sprouting in a crevice and plant roots exert physical pressure as well as providing a pathway for water and chemical infiltration.{{sfn|Blatt|Middleton|Murray|1980|pp=249-250}}