Impact of environmental factors and tributary contributions on tidal dissolved organic matter dynamics

Tang，Gang1,2; Wang，Qianqian1

2022-12-01

10.1016/j.chemosphere.2022.136384

CHEMOSPHERE   Impact Factor & Quartile

0045-6535

1879-1298

Riverine dissolved organic matter (DOM) transport was a key step in the carbon biogeochemical cycle while we had limited understanding of its contribution to the estuary DOM dynamics. This study focused on the river downstream-to-tidal estuary DOM variation and the control of environmental factors on it. The contributions of three tributaries with varing urbanization degrees to the tidal DOM dynamics were evaluated. Though more aromatics were introduced to the urban tributary, the A/A values and fluorescent index values indicated the DOM molecular size was uniformly reduced due to the enhanced microbial degradation during transport. The tidal DOM showed less varied spectroscopic indexes than the tributary DOM, but tidal cycles strongly impacted the fluorescent DOM quantified by the fluorescence regional integration (FRI). Salinity range can differentiate the fluorescent DOM variation patterns in river tributaries (e.g., <2.5, positive correlations; >2.5, negative correlations) and tidal cycles (>10, negative correlations). For tidal DOM, the high salinity decreased more humic-related components, resulting in increased proportions of protein-related components in high tides. The dissolved oxygen and nitrogen contents were negatively correlated with salinity, suggesting the microbial contributions and anthropogenic inputs in tributaries increased the tidal DOM quantity. The less urbanized tributaries contributed more to the low-tide DOM compositions/properties while the dynamic contribution of the urban tributary impacted more the tidal DOM dynamics. Our results highlighted the uneven declines of FRI values of different components by freshwater-saltwater mixing in estuaries and suggested the different functioning of urban, agro-urban, and suburban tributaries contributed to tidal DOM dynamics.

Dissolved organic matter Estuary mixing Salinity Tidal cycle Tributary contribution

SCI

English

First ; Corresponding

China Postdoctoral Science Foundation[2021M701587];National Natural Science Foundation of China[42107055];

Environmental Sciences & Ecology

Environmental Sciences

WOS:000890363100005

PERGAMON-ELSEVIER SCIENCE LTD

ENVIRONMENT/ECOLOGY

2-s2.0-85138797749

Scopus

1.State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.Climate & Energy College,School of Geography,Earth and Atmospheric Sciences,The University of Melbourne,VIC,Melbourne,3010,Australia

Tang，Gang,Wang，Qianqian. Impact of environmental factors and tributary contributions on tidal dissolved organic matter dynamics[J]. CHEMOSPHERE,2022,308.

Tang，Gang,&Wang，Qianqian.(2022).Impact of environmental factors and tributary contributions on tidal dissolved organic matter dynamics.CHEMOSPHERE,308.

Tang，Gang,et al."Impact of environmental factors and tributary contributions on tidal dissolved organic matter dynamics".CHEMOSPHERE 308(2022).