Sedimentary organic matter molecular composition reveals the eutrophication of the past 500 years in Lake Daihai, Inner Mongolia

Chukun Hu; Hai Xu; Siwei Shi; Jianghu Lan; Kang'en Zhou; Jin Zhang; Yunping Song; Jing Wang; Pingqing Fu

doi:10.1016/j.envres.2023.115753

Sedimentary organic matter molecular composition reveals the eutrophication of the past 500 years in Lake Daihai, Inner Mongolia

Environ Res. 2023 Jun 15:227:115753. doi: 10.1016/j.envres.2023.115753. Epub 2023 Mar 23.

Authors

Chukun Hu¹, Hai Xu², Siwei Shi¹, Jianghu Lan³, Kang'en Zhou¹, Jin Zhang⁴, Yunping Song¹, Jing Wang¹, Pingqing Fu¹

Affiliations

¹ Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, PR China.
² Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, PR China. Electronic address: xuhai@tju.edu.cn.
³ State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, PR China.
⁴ Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, PR China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, PR China.

PMID: 36965811
DOI: 10.1016/j.envres.2023.115753

Abstract

Lake eutrophication seriously threatens water quality and human health. Under continuous global warming and intensified human activity, increasing attention is being paid to how lake trophic status responds to climate change and anthropogenic impacts. Based on the sedimentary organic matter (SOM) molecular composition determined by the Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) technology, and combined with the SOM stable nitrogen isotopes (δ¹⁵N_org), we studied how lake trophic status and ecology respond to both climatic changes and anthropogenic impacts of the past 500 yrs at Lake Daihai, Inner Mongolia. The results show that the relative abundance of lipids, proteins, and carbohydrates in lake sediments kept relatively low before AD ∼1850, and increased gradually thereafter, especially after AD ∼1950, suggesting that the lake trophic status was low before AD ∼1850, but obviously increased during the past one more century. On the other hand, the relative abundance of allochthonous condensed aromatics and vascular plant-derived polyphenols compounds gradually decreased after AD ∼1850, which is most likely due to the intensified land-use changes in the catchment. Our results show that the SOM molecular composition is more sensitive to trace the land-use changes than the δ¹⁵N_org ratios, suggesting a potential use of this technique to trace even earlier human land uses (e.g., during the prehistorical times) in a catchment. The results of this study suggest that intensified land-use change, increased discharges of human sewage and industrial wastewater, cropland runoff, and concentrated effects caused by lake level drops may have combinedly increased nutrient concentration and accelerated lake eutrophication at Lake Daihai. Therefore, proper policy is necessary to slow down anthropogenic impacts and limit further eutrophication for lakes like Lake Daihai.

Keywords: Anthropogenic impacts; Climate changes; Eutrophication; Lake Daihai; Molecular composition; Nitrogen isotopes.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

China
Eutrophication
Geologic Sediments* / analysis
Humans
Lakes* / chemistry
Nitrogen / analysis
Water Quality

Substances

Nitrogen