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Soil sulphur speciation in two glacier forefield soil chronosequences assessed by S K ‐edge XANES spectroscopy
Author(s) -
Prietzel J.,
Wu Y.,
Dümig A.,
Zhou J.,
Klysubun W.
Publication year - 2013
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12032
Subject(s) - topsoil , pedogenesis , environmental chemistry , chemistry , glacier , genetic algorithm , soil water , soil science , geology , ecology , geomorphology , biology
Summary In regions with little atmospheric input of sulphur ( S ) and S ‐poor parent material, the bio‐availability of S , which is dependent on its speciation, may limit ecosystem production and succession. In our study, soil S speciation in two glacier forefield soil chronosequences ( H ailuogou G lacier, G ongga S han, C hina; D amma G lacier, S wiss A lps) was investigated for the first time. Different S species were quantified by synchrotron‐based X ‐ray absorption near‐edge structure ( XANES ) spectroscopy at the S K ‐edge. Both chronosequences show similar patterns and pedogenetic trends of their topsoil S status. Topsoil concentrations of total S were correlated with the concentrations of organic carbon and pedogenic Fe/Al oxyhydroxides. Both moraine materials contained inorganic sulphides, which in the topsoil were oxidized within 30 ( H ailuogou) or 75 years ( D amma) of soil development after deglaciation. About 50% of total S in the fresh moraine material at H ailuogou and 75% of that in the 15 year‐old soil at D amma was organically‐bound. During initial soil development, the contribution of organic S to total S increased at the expense of inorganic sulphide and sulphate, resulting in organic S percentages > 90% of total topsoil S after 30 ( H ailuogou) and 75 ( D amma) years of pedogenesis. Organic S compounds with electronic oxidation states of the S atom > + 1.5 (sulphoxides, sulphones, sulphonates and ester sulphates) dominated the organic S pool in all soils. Hence, microbial degradation of non‐sulphide organic S (sulphonates and ester sulphates) is probably important to mitigate S scarcity caused by limited availability of SO 4 2 − ‐ S in these soils. Changes in topsoil S speciation during initial stages of pedogenesis and ecosystem succession in glacier forefields under a cool, humid climate appear to be governed by combined effects of mineral weathering (oxidation of inorganic sulphides and formation of S ‐adsorbing sesquioxides), accumulation and microbial turnover of soil organic matter and the type of vegetation succession.