Deciphering the link between particulate organic matter molecular composition and lake eutrophication by FT-ICR MS analysis

Minli Guo; Mingxing Yu; Xu Wang; Naidong Xiao; Arnaud Huguet; Yunlin Zhang; Guanglong Liu

doi:10.1016/j.watres.2024.122936

Deciphering the link between particulate organic matter molecular composition and lake eutrophication by FT-ICR MS analysis

Water Res. 2024 Dec 7:272:122936. doi: 10.1016/j.watres.2024.122936. Online ahead of print.

Authors

Minli Guo¹, Mingxing Yu², Xu Wang³, Naidong Xiao¹, Arnaud Huguet⁴, Yunlin Zhang⁵, Guanglong Liu⁶

Affiliations

¹ College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, PR China.
² Changjiang Basin Ecology and Environment Monitoring and Scientific Research Center, Changjiang Basin Ecology and Environment Administration, Ministry of Ecology and Environment, Wuhan 430010, China.
³ River Basin Complex Administration, China Three Gorges Corporation, Yichang, 443133, China.
⁴ Sorbonne Université, CNRS, EPHE, PSL, UMR METIS, F-75005 Paris, France.
⁵ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
⁶ College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, PR China. Electronic address: liugl@mail.hzau.edu.cn.

PMID: 39674138
DOI: 10.1016/j.watres.2024.122936

Abstract

Eutrophication has emerged as a significant environmental problem for global lakes. As an essential carrier of nutrients, particulate organic matter (POM) plays a vital role in the eutrophication process of these aquatic systems. In this study, POM from seven lakes with different trophic states in the middle and lower reaches of the Yangtze River (China) was characterized using carbon and nitrogen stable isotopes and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The aim was to elucidate the relationship between the source and molecular composition of POM during the eutrophication process of lakes. The results indicated that POM was mainly composed of autochthonous (62.7%) and allochthonous (37.3%) sources, with the contribution from autochthonous sources being more pronounced across the different sources. The POM formulas mainly consisted of the subclasses CHO, CHON, CHOP, CHOS, and CHONS. Notably, CHOP formulas had the highest proportion of labile formula compounds, according for 51.56%. The unsaturation, aromaticity, and oxidation of unique POM formulas gradually decreased with increasing trophic states. A significant positive correlation was observed between CHOP and the percentage of labile compounds (MLB_L%) in unique POM formulas. The relative abundance of lipid and protein compounds of unique POM formulas showed a positive correlation with lake trophic states, which indicated that with the increase of lake trophic states, the content of autochthonous POM gradually increased. Herein, we inferred that with the intensification of lake eutrophication, the autochthonous POM increased, which was accompanied by a further increase of labile P-containing compounds in POM, thus leading to the increasing eutrophication process of lakes in the form of positive feedback. Overall, this investigation of POM at the molecular level illustrates the deep-rooted mechanism of frequent lake eutrophication. This is of great significance in understanding the fate of POM and effectively controlling lake eutrophication.

Keywords: FT-ICR MS; Molecular composition; Particulate organic matter (POM); Source; Trophic states.