Jiang Juan, Zhu Yuanrong, He Zhongqi, Bing Xiaojie, Wang Kuo, Ma Huihui, Liu Fan, Ding Jing, Wei Jian
State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
USDA-ARS, Southern Regional Research Center, 1100 Allen Toussaint Blvd., New Orleans, LA 70124, USA.
Heliyon. 2023 Mar 23;9(4):e14797. doi: 10.1016/j.heliyon.2023.e14797. eCollection 2023 Apr.
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 ( < 0.05). Within the DOM, TFe was correlated with the amino acid tryptophan ( < 0.01). There was also a strong positive correlation between total P (TP) concentrations in DOM and tyrosine ( < 0.01). Organic P (P) comprised most of the DOM TP, and was related to dissolved organic carbon (DOC) content and the amino acid tyrosine ( < 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.
溶解有机物（DOM）在生态系统中起着重要作用，影响着铁（Fe）和磷（P）的归宿与迁移。为了更好地理解这些成分的地球化学循环，在中国东北典型温带森林下游的一个水库周围采集了土壤和沉积物样本。从这些土壤、河流和水库沉积物中提取了DOM组分，然后用光谱技术进行表征。比较表征数据表明，西山水库的DOM库部分是自生的，来源于上游陆地生态系统中物质的径流和沉积。水库上游DOM提取物中的总铁（TFe）含量明显低于水库中的含量（<0.05）。在DOM中，TFe与氨基酸色氨酸相关（<0.01）。DOM中的总磷（TP）浓度与酪氨酸之间也存在很强的正相关（<0.01）。有机磷（P）占DOM中TP的大部分，并且与溶解有机碳（DOC）含量和氨基酸酪氨酸相关（<0.01）。DOM、Fe和P之间的相互作用似乎是由于与色氨酸（Fe）和酪氨酸（P）的络合。这表明在最佳条件下，Fe-DOM-P的形成比DOM-Fe-P络合物更容易产生。DOM、Fe和P之间的相互作用可以促进与DOM络合的组分在河流和水库生态系统中的协同迁移、转化和最终归宿，最终导致在水库内积累，并在水库大坝放水时输送到下游地区。水库大坝可以有效地拦截DOM和矿物质，防止其向下游流动；然而，了解DOM、Fe和P在水库、下游河流以及最终在海洋中的共同循环非常重要。DOM的氨基酸组分酪氨酸和色氨酸参与DOM络合这一问题需要进一步研究。
