论文题目:

Characterization of CDOM in saline and freshwater lakes across China using spectroscopic analysis

英文论文题目:

Characterization of CDOM in saline and freshwater lakes across China using spectroscopic analysis

第一作者:

宋开山

英文第一作者:

Kai S.Song

联系作者:

宋开山

英文联系作者:

Kai S.Song

发表年度:

2019

卷:

150

页码:

403-417

摘要:

Colored dissolved organic matter (CDOM) is a major component of DOM in waters, and plays a vital role in carbon cycling in inland waters. In this study, the light absorption and three-dimensional excitation-emission matrix spectra (EEMs) of CDOM of 936 water samples collected in 2014–2017 from 234 lakes in five regionsacross China were examined to determine relationships between lake water sources (fresh versus saline) and their fluorescence/absorption characteristics. Results indicated significant differences regarding DOC concentration and aCDOM(254) between freshwater (6.68？mg？C L？1, 19.55？m-1) and saline lakes (27.4？mg？C L？1, 41.17？m-1). While humic-like (F5) and fulvic-like (F3) compounds contributed to CDOM fluorescence in all lake waters significantly, their contribution to total fluorescence intensity (FT) differed between saline and freshwater lakes. Significant negative relationships were also observed between lake altitude with either F5 (R2？=？0.63, N？=？306) or FT (R2？=？0.64, N？=？306), suggesting that the abundance of humic-like materials in CDOM tends to decrease with increased in lakes altitude. In high-altitude lakes, strong solar irradiance and UV exposure may have induced photo-oxidation reactions resulting in decreased abundance of humic-like substances and the formation of low molecular weight compounds. These findings have important implications regarding our understanding of C dynamics in lacustrine systems and the contribution of these ecosystems to the global C cycle.

英文摘要:

Colored dissolved organic matter (CDOM) is a major component of DOM in waters, and plays a vital role in carbon cycling in inland waters. In this study, the light absorption and three-dimensional excitation-emission matrix spectra (EEMs) of CDOM of 936 water samples collected in 2014–2017 from 234 lakes in five regionsacross China were examined to determine relationships between lake water sources (fresh versus saline) and their fluorescence/absorption characteristics. Results indicated significant differences regarding DOC concentration and aCDOM(254) between freshwater (6.68？mg？C L？1, 19.55？m-1) and saline lakes (27.4？mg？C L？1, 41.17？m-1). While humic-like (F5) and fulvic-like (F3) compounds contributed to CDOM fluorescence in all lake waters significantly, their contribution to total fluorescence intensity (FT) differed between saline and freshwater lakes. Significant negative relationships were also observed between lake altitude with either F5 (R2？=？0.63, N？=？306) or FT (R2？=？0.64, N？=？306), suggesting that the abundance of humic-like materials in CDOM tends to decrease with increased in lakes altitude. In high-altitude lakes, strong solar irradiance and UV exposure may have induced photo-oxidation reactions resulting in decreased abundance of humic-like substances and the formation of low molecular weight compounds. These findings have important implications regarding our understanding of C dynamics in lacustrine systems and the contribution of these ecosystems to the global C cycle.

刊物名称:

Water Research

英文刊物名称:

Water Research

参与作者：

K. S. Song, Y. X. Shang, Z. D. Wen, P. A. Jacinthe, G. Liu, L. L. Lyu and C. Fang

英文参与作者：

K. S. Song, Y. X. Shang, Z. D. Wen, P. A. Jacinthe, G. Liu, L. L. Lyu and C. Fang