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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #363521

Research Project: Increasing the Value of Cottonseed

Location: Commodity Utilization Research

Title: Linking the molecular composition of autochthonous dissolved organic matter to source identification for freshwater lake ecosystems by combination of optical spectroscopy and FT-ICR-MS analysis

Author
item LIU, SHASHA - Chinese Research Academy Of Environmental Sciences
item He, Zhongqi
item ZHI, TANG - Chinese Research Academy Of Environmental Sciences
item LIU, LEIZHEN - Beijing Normal University
item HOU, JUNWEN - Chinese Research Academy Of Environmental Sciences
item LI, TINGTING - Chinese Research Academy Of Environmental Sciences
item ZHANG, YAHE - China University Of Petroleum
item SHI, QUAN - China University Of Petroleum
item GIESY, JOHN - University Of Saskatchewan
item WU, FENGCHANG - Chinese Research Academy Of Environmental Sciences

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2019
Publication Date: 2/10/2020
Citation: Liu, S., He, Z., Zhi, T., Liu, L., Hou, J., Li, T., Zhang, Y., Shi, Q., Giesy, J.P., Wu, F. 2020. Linking the molecular composition of autochthonous dissolved organic matter to source identification for freshwater lake ecosystems by combination of optical spectroscopy and FT-ICR-MS analysis. Science of the Total Environment. 703:134764. https://doi.org/10.1016/j.scitotenv.2019.134764.
DOI: https://doi.org/10.1016/j.scitotenv.2019.134764

Interpretive Summary: Dissolved organic matter (DOM) is a compositional diverse assembly of molecules that is ubiquitous in natural waters. Increased knowledge of the composition of DOM will allow a better understanding on how it plays its biogeochemical functions (e.g., mobility, bioavailability and effects in the fate of organic pollutants and trace metals). Therefore, end-member DOM samples of macrophytes, algae and sediments and freshwaters DOM samples in two eutrophic lakes (Taihu and Dianchi) were collected and characterized by ultraviolet-visible (UV-vis) spectroscopy, fluorescence spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The UV-vis indicator of aromaticity covaried with polyphenolic and polycyclic aromatics, whereas those reflecting autochthonous end-members covaried with more aliphatic compounds. Multivariate analysis of FT-ICR-MS data of end-members and freshwaters samples revealed the predominant terrestrial input to Tai Lake and greater contribution of algae released DOM to Lake Dianchi. Data in this study provide critical information on the freshwater lake DOM characteristics at a molecular level and will benefit for source identification of DOM input in natural freshwater ecosystems.

Technical Abstract: Autochthonous dissolved organic matter (DOM) is increasingly released in lakes due to eutrophication and algal bloom, and thus affects lake DOM pool. However, there are only limited studies on the molecular characteristics of autochthonous DOM and its influencing mechanisms. Therefore, end-member DOM samples of macrophytes, algae and sediments and freshwaters DOM samples in eutrophic lakes (Ch:Taihu and Dianchi) were collected and characterized by ultraviolet-visible (UV-vis) spectroscopy, fluorescence spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The results revealed that the chemical structures of algae-derived DOM were more saturated and less oxidized with greater contents of lipid (56.81%) and protein (30.92%) compounds, while macrophyte-derived DOM composition was relatively more aromatic, predominant by lignin-like (50.58%) and tannin (17.39%) compounds. Sediment-derived DOM contained more N-containing compoundswith lignin-like (51.19-59.70%) and protein (23.48-30.31%) substances. The UV-vis indicator of aromaticity covaried with polyphenolic and polycyclic aromatics, whereas those reflecting autochthonous end-members covaried with more aliphatic compounds. Multivariate analysis of FT-ICR-MS dada of end-members and freshwaters samples revealed the predominant terrestrial input to Tai Lake and greater contribution of algae released DOM to Lake Dianchi. This study provides critical information about autochthonous DOM characteristics at a molecular level and will benefit for source identification of DOM in natural freshwaters by the combination of multivariate analysis with FT-ICR-MS.