DOI: 10.1111/gcb.12229
论文题名: Iron oxidation stimulates organic matter decomposition in humid tropical forest soils
作者: Hall S.J. ; Silver W.L.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2013
卷: 19, 期: 9 起始页码: 2804
结束页码: 2813
语种: 英语
英文关键词: Carbon cycle
; Iron oxidation
; Iron reduction
; Oxidative enzyme
; Oxygen
; Soil organic matter
; Soil respiration
; Tropical forest
Scopus关键词: carbon dioxide
; iron
; oxidoreductase
; oxygen
; phenol derivative
; soil organic matter
; carbon cycle
; decomposition
; forest soil
; iron
; oxidation
; soil organic matter
; soil respiration
; tropical forest
; article
; bioremediation
; carbon cycle
; chemistry
; humidity
; iron oxidation
; iron reduction
; metabolism
; oxidation reduction reaction
; soil
; soil respiration
; tree
; tropic climate
; tropical rain forest
; carbon cycle
; iron oxidation
; iron reduction
; oxidative enzyme
; oxygen
; soil organic matter
; soil respiration
; tropical forest
; Biodegradation, Environmental
; Carbon Dioxide
; Humidity
; Iron
; Oxidation-Reduction
; Phenols
; Soil
; Trees
; Tropical Climate
英文摘要: Humid tropical forests have the fastest rates of organic matter decomposition globally, which often coincide with fluctuating oxygen (O2) availability in surface soils. Microbial iron (Fe) reduction generates reduced iron [Fe(II)] under anaerobic conditions, which oxidizes to Fe(III) under subsequent aerobic conditions. We demonstrate that Fe (II) oxidation stimulates organic matter decomposition via two mechanisms: (i) organic matter oxidation, likely driven by reactive oxygen species; and (ii) increased dissolved organic carbon (DOC) availability, likely driven by acidification. Phenol oxidative activity increased linearly with Fe(II) concentrations (P < 0.0001, pseudo R2 = 0.79) in soils sampled within and among five tropical forest sites. A similar pattern occurred in the absence of soil, suggesting an abiotic driver of this reaction. No phenol oxidative activity occurred in soils under anaerobic conditions, implying the importance of oxidants such as O2 or hydrogen peroxide (H2O2) in addition to Fe(II). Reactions between Fe(II) and H2O2 generate hydroxyl radical, a strong nonselective oxidant of organic compounds. We found increasing consumption of H2O2 as soil Fe(II) concentrations increased, suggesting that reactive oxygen species produced by Fe(II) oxidation explained variation in phenol oxidative activity among samples. Amending soils with Fe(II) at field concentrations stimulated short-term C mineralization by up to 270%, likely via a second mechanism. Oxidation of Fe(II) drove a decrease in pH and a monotonic increase in DOC; a decline of two pH units doubled DOC, likely stimulating microbial respiration. We obtained similar results by manipulating soil acidity independently of Fe(II), implying that Fe(II) oxidation affected C substrate availability via pH fluctuations, in addition to producing reactive oxygen species. Iron oxidation coupled to organic matter decomposition contributes to rapid rates of C cycling across humid tropical forests in spite of periodic O2 limitation, and may help explain the rapid turnover of complex C molecules in these soils. © 2013 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/62352
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Environmental Science, Policy, and Management, University of California-Berkeley, 107 Mulford Hall, Berkeley, CA, 94720, United States
Recommended Citation:
Hall S.J.,Silver W.L.. Iron oxidation stimulates organic matter decomposition in humid tropical forest soils[J]. Global Change Biology,2013-01-01,19(9)