Biological weathering and the long‐term carbon cycle: integrating mycorrhizal evolution and function into the current paradigm

作者：Lyla L. Taylor, Jonathan R. Leake, Joe Quirk, Kathleen Hardy, Steven A. Banwart, David J. Beerling · 发表于：Geobiology · 年份：2009 · DOI：10.1111/j.1472-4669.2009.00194.x · 被引用次数：337 · 研究领域：Mycorrhizal Fungi and Plant Interactions、Plant Diversity and Evolution、Paleontology and Stratigraphy of Fossils

The dramatic decline in atmospheric CO2 evidenced by proxy data during the Devonian (416.0-359.2 Ma) and the gradual decline from the Cretaceous (145.5-65.5 Ma) onwards have been linked to the spread of deeply rooted trees and the rise of angiosperms, respectively. But this paradigm overlooks the coevolution of roots with the major groups of symbiotic fungal partners that have dominated terrestrial ecosystems throughout Earth history. The colonization of land by plants was coincident with the rise of arbuscular mycorrhizal fungi (AMF),while the Cenozoic (c. 65.5-0 Ma) witnessed the rise of ectomycorrhizal fungi (EMF) that associate with both gymnosperm and angiosperm tree roots. Here, we critically review evidence for the influence of AMF and EMF on mineral weathering processes. We show that the key weathering processes underpinning the current paradigm and ascribed to plants are actually driven by the combined activities of roots and mycorrhizal fungi. Fuelled by substantial amounts of recent photosynthate transported from shoots to roots, these fungi form extensive mycelial networks which extend into soil actively foraging for nutrients by altering minerals through the acidification of the immediate root environment. EMF aggressively weather minerals through the additional mechanism of releasing low molecular weight organic chelators. Rates of biotic weathering might therefore be more usefully conceptualized as being fundamentally controlled by the biomass, surface area of ...