Fungal involvement in bioweathering and biotransformation of rocks and minerals

Abstract

In the Earth’s lithosphere, fungi are of fundamental importance as decomposer organisms, animal and plant pathogens and symbionts (e.g. lichens and mycorrhizas), being ubiquitous in sub-aerial and subsoil environments. The ability of fungi to interact with minerals, metals, metalloids and organic compounds through biomechanical and biochemical processes, makes them ideally suited as biological weathering agents of rock and building stone. They also play a fundamental role in biogeochemical cycling of nutrients, (e.g. C, N, P and S) and metals (e.g. Na, Mg, Ca, Mn, Fe, Cu, Zn, Co and Ni) essential for the growth of living organisms in the biosphere. In addition they play an integral role in the mobilization and immobilization of non-essential metals (e.g. Cs, Al, Cd, Hg and Pb). Most studies on mineral-microbe interactions and microbial involvement in geological processes have concentrated on bacteria and archaea (Prokaryota): fungi (Eukaryota) have, to a certain extent, been neglected. This article addresses the role of fungi in geomicrobiological processes, emphasizing their deteriorative potential on rock, building stone and mineral surfaces and involvement in the formation of secondary mycogenic minerals. Such roles of fungi are also of importance for the global carbon reservoir and have potential biotechnological applications, e.g. in the bioremediation of xenobiotic-, metal- and/or radionuclide-contaminated soils and wastes, and metal/radionuclide recovery.

Investigating the role of microbes in mineral weathering: Nanometre-scale characterisation of the cell–mineral interface using FIB and TEM

“…Numerous studies on microbe-mineral interactions have shown that micro-organisms substantially affect the process of mineral weathering (termed "bioweathering" hereafter) (Burford et al, 2003;Gadd, 2007;Hoffland et al, 2004;Hutchens et al, 2003;Kalinowski et al, 2000). Despite this increasing evidence that microbial cells can play a major role in mineral alteration, the processes occurring at the cell-mineral interface remain poorly understood.…”

The roles of endolithic fungi in bioerosion and disease in marine ecosystems. I. General concepts

“…The study of the roles of fungi in geologically relevant processes, such as metal and mineral transformations, can be termed geomycology, an important part of the more general area of geomicrobiology (Gadd 2007, 2010). In the terrestrial environment, such processes are important in rock bioweathering, contributing to the formation and development of mineral soil, and global biogeochemical cycles for component elements, including their availability to living organisms (Sterflinger 2000; Burford et al 2003; Gadd 2007). In aerobic terrestrial environments, free-living and symbiotic fungi are of great importance, especially when considering rock surfaces, soil and the plant root–soil interface.…”

“…Fossilised fungal structures have been reported from a variety of mineral substrates including Devonian Rhynie Chert, as fossil lichen mycobionts in stromatolites, in Djebel-Onk phosphorites, Triassic silicified rock, Bitterfield amber and Tertiary Dominican amber (see Burford et al 2003). Various types of endoliths, including fungi, have been found in marine shells in the Late Ordovician and Middle Devonian volcanic rocks, while microborings have also been found in early Cambrian phosphatic and phosphatised fossils (Taylor et al 2015).…”

“…Rocks and minerals represent a vast reservoir of elements and compounds, many of which are essential to life and which must be released in specific soluble forms which can be assimilated by the biota (Burford et al 2003). These include essential metals as well as nutrients like phosphate.…”

“…hot and cold deserts (Staley et al 1982; Gorbushina et al 1993; Sterflinger 2000; Verrecchia 2000). It is likely that fungi are ubiquitous members of the microbiota of all rocks, occurring over a wide range of geographical and climatic zones (Burford et al 2003). Free-living and symbiotic fungi are therefore associated with elements besides O that account for over 99.9% of crustal rocks (e.g.…”