deletions | additions       diff --git a/Fuelled_by_carbohydrate_supplied_by__.md b/Fuelled_by_carbohydrate_supplied_by__.md  index 2ff14d0..0ae7ba2 100644  --- a/Fuelled_by_carbohydrate_supplied_by__.md  +++ b/Fuelled_by_carbohydrate_supplied_by__.md 
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#Fungal weathering in the lab  Fuelled by carbohydrate supplied by the host, many ectomycorrhizal fungi have the capacity to acidify the surrounding substrate and exude organic acids, both when growing in axenic cultures and in symbiosis with plants under laboratory conditions (\cite{Rosling_2009}, \cite{Hoffland_2004}, \cite{Schmalenberger_2015}. Using flow through systems, \cite{Calvaruso_2013} estimated weathering rates to be 10 times higher when ectomycorrhizal pine seedlings were present compared to unplanted systems, and attributed this to exudation of organic acids and acidifying effects by the EMF fungus. There is however, a large step to transfer these results to natural systems according to the authors.   Similar activities can be performed by other microorganisms in the soil. For instance, many soil bacteria have a strong capacity to acidify the surrounding when sufficient carbon resources is available. Trees foster specific communities of bacteria in the rhizosphere, or mycorrhizasphere (\cite{Collignon_2011}, \cite{Calvaruso_2013}Calvarusu 2008), and these organisms may be the active partner of weathering reactions in the soil (review by \cite{Uroz_2009}). In addition, brown rotting fungi produce large amounts of oxalic acids when degrading wood (ref), which may have secondary effects on phosphorous release from the soil (\cite{Fransson_2004}.    It is not clear if organic acid release and acidification is a primary mechanism to release nutrients from soil minerals, or a secondary effect related to the way microorganisms are growing in the soil. Proton are exuded in response to uptake of positively charged ions regardless of if minerals are present or not, and exudation of organic acids can occur in response to many different factors (ref). Furthermore, concentrations of organic acids in soil solution (Hees et al) solution\cite{van_Hees_2000}  seldom reach levels that have significant effects on mineral dissolution (ref). dissolution\cite{chadwick_changing_1999}.  On the other hand, fungal hyphae attach to surfaces to be able to grow and proliferate through the soil, which may affect the surface of the minerals both physically and chemically (McMaster 2014). Attachment is enhanced by organic compounds produced by the fungus (Denny and Wilkins 1987, Gadd and Sayer 2000 in adeke) and Balogh-Brunstad suggested that organic acids may accumulate under such biolayers to sufficient concentrations to affect mineral dissolution. Although these authors call for more experiments to confirm this possible effect.