| Title |
Changes in Spectroscopic and Molecular Weight Characteristics of Dissolved Organic Matter in an Agriculture Reservoir during a Summer Monsoon |
| Authors |
정가영 ( Ka-Young Jung ) ; 이윤경 ( Yun Kyung Lee ) ; 유하영 ( HaYoung Yoo ) ; 남귀숙 ( Gui-sook Nam ) ; 허진 ( Jin Hur ) |
| DOI |
https://doi.org/10.15681/KSWE.2021.37.6.458 |
| Keywords |
Dissolved organic matter; Fluorescence; Multivariate statistics; Size exclusion chromatography; Summer monsoon |
| Abstract |
In this study, we investigated the variations of dissolved organic matter (DOM) in an agricultural reservoir during the monsoon period (June to October, 2020) with respect to the organic carbon concentration (DOC), molecular weight distribution, and optical properties. The monsoon period was divided into three phases - beginning storm (BS), during storm (DS), and after storm (AS). Our results showed significant differences in the concentrations and characteristics of DOM during the summer monsoon. The DOC concentrations were decreased after the monsoon, probably due to a dilution effect. In contrast, increasing trends were observed in the specific UV absorbance (SUVA), and relative abundances of humic-like fluorescence and larger-sized compounds. These observations implied that the large-sized and humic-like organic components with terrestrial origins strongly affected the reservoir DOM after the summer monsoon. Meanwhile, biopolymer size fraction, which is associated with algal activity, became more abundant after the monsoon. These results suggest that DOM with autochthonous sources became dominant as a result of the inflow of nutrients into the reservoir after the storm. Spatial changes in DOM within the reservoir were not pronounced as much as the temporal variations. All taken, it can be concluded that the summer monsoon simply led to the decrease of DOM concentrations while the sources and the quality of DOM underwent substantial changes, which may enrich refractory organic matter in the reservoir. This study reveals the importance of in-depth DOM quality monitoring before and after summer monsoon for effective water quality management in agricultural reservoirs. |