Multiple spectral comparison of dissolved organic matter in the drainage basin of a reservoir in Northeast China: Implication for the interaction among organic matter, iron, and phosphorus

Juan Jiang; Yuanrong Zhu; Zhongqi He; Xiaojie Bing; Kuo Wang; Huihui Ma; Fan Liu; Jing Ding; Jian Wei

doi:10.1016/j.heliyon.2023.e14797

Multiple spectral comparison of dissolved organic matter in the drainage basin of a reservoir in Northeast China: Implication for the interaction among organic matter, iron, and phosphorus

Heliyon. 2023 Mar 23;9(4):e14797. doi: 10.1016/j.heliyon.2023.e14797. eCollection 2023 Apr.

Authors

Juan Jiang¹, Yuanrong Zhu¹, Zhongqi He², Xiaojie Bing^{1

3}, Kuo Wang¹, Huihui Ma¹, Fan Liu⁴, Jing Ding⁴, Jian Wei¹

Affiliations

¹ State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
² USDA-ARS, Southern Regional Research Center, 1100 Allen Toussaint Blvd., New Orleans, LA 70124, USA.
³ School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China.
⁴ School of Environment, Harbin Institute of Technology, Harbin 150090, China.

Abstract

Dissolved organic matter (DOM) plays a major role in ecological systems, affecting the fate and transportation of iron (Fe) and phosphorus (P). To better understand the geochemical cycling of these components, soil and sediment samples were collected around a reservoir downstream of a typical temperate forest in Northeast China. The DOM fractions from these soils, river, and reservoir sediments were extracted and then characterized by spectroscopic techniques. Comparative characterization data showed that the DOM pool of the Xishan Reservoir was partly autochthonous and derived from runoff and deposition of material in terrestrial ecosystems upstream. The upper reaches of the reservoir had significantly lower total Fe (TFe) content in the DOM extracts than those found in the reservoir (p < 0.05). Within the DOM, TFe was correlated with the amino acid tryptophan (p < 0.01). There was also a strong positive correlation between total P (TP) concentrations in DOM and tyrosine (p < 0.01). Organic P (P_o) comprised most of the DOM TP, and was related to dissolved organic carbon (DOC) content and the amino acid tyrosine (p < 0.01). The interaction among DOM, Fe, and P appears to be due to complexation with tryptophan (Fe) and tyrosine (P). This suggests that the formation of Fe-DOM-P would be produced more readily than DOM-Fe-P complexes under optimal conditions. The interaction among DOM, Fe, and P can promote the coordinated migration, transformation, and ultimate fate of components that are complex with DOM from riverine and reservoir ecosystems, ultimately leading to accumulation within a reservoir and transport to downstream regions when reservoir dams are released. Reservoir dams can effectively intercept DOM and minerals prevent its flow downstream; however, it is important to understand the co-cycling of DOM, Fe and P within reservoirs, downstream rivers, and ultimately oceans. The involvement of amino acid components of DOM, tyrosine and tryptophan, in DOM complexation is an issue that requires further study.

Keywords: Dissolved organic matter; Fe-DOM-P; Forest; Geochemical cycling; Reservoir.