Electrochemical and spectroscopic characteristics of dissolved organic matter in a forest soil profile.
Dissolved organic matter (DOM) represents one of the most mobile and reactive organic compounds in ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Electrochemical methods were first employed to evaluate DOM redox properties, and spectroscopic approaches were utilized to obtain information concerning its composition and structure. DOM was extracted from a forest soil profile with five horizons. Differential pulse voltammetry indicated that there were more redox-active moieties in the DOM from upper horizons than in that from lower horizons. Cyclic voltammetry further showed that these moieties were reversible in electron transfer. Chronoamperometry was employed to quantify the electron transfer capacity of DOM, including electron acceptor capacity and electron donor capacity, both of which decreased sharply with increasing depth. FT-IR, UV-Vis and fluorescence spectra results suggested that DOM from the upper horizons was enriched with aromatic and humic structures while that from the lower horizons was rich in aliphatic carbon, which supported the findings obtained by electrochemical approaches. Electrochemical approaches combined with spectroscopic methods were applied to evaluate the characteristics of DOM extracted along a forest soil profile. The electrochemical properties of DOM, which can be rapidly and simply obtained, provide insight into the migration and transformation of DOM along a soil profile and will aid in better understanding of the biogeochemical role of DOM in natural environments.
Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. br19870805@sina.com
Ran
R
Bi
Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
Qin
Q
Lu
Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
Tian
T
Yuan
Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
Shungui
S
Zhou
Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
Yong
Y
Yuan
College of Resources and Environment, South China Agricultural University, Guangzhou 510642, China.
Yanfei
Y
Cai
D055664:Electrochemical Techniques; D004784:Environmental Monitoring / Q000379:methods; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D014197:Trees
D012987:Soil; D012989:Soil Pollutants