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

Authors: JIANG, JUAN - Chinese Research Academy Of Environmental Sciences; ZHU, YUANRONG - Chinese Research Academy Of Environmental Sciences; He, Zhongqi; BING, XIAOJIE - Chinese Research Academy Of Environmental Sciences; WANG, KUO - Chinese Research Academy Of Environmental Sciences; MA, HUIHUI - Chinese Research Academy Of Environmental Sciences; LIU, FAN - Harbin Institute Of Technology (HIT); DING, JING - Harbin Institute Of Technology (HIT); WEI, JIAN - Chinese Research Academy Of Environmental Sciences

Submitted to: Heliyon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2023
Publication Date: 3/23/2023
Citation: Jiang, J., Zhu, Y., He, Z., Bing, X., Wang, K., Ma, H., Liu, F., Ding, J., Wei, J. 2023. 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. 9. Article e14797. https://doi.org/10.1016/j.heliyon.2023.e14797.
DOI: https://doi.org/10.1016/j.heliyon.2023.e14797

Interpretive Summary: Dissolved organic matter (DOM) is one of the largest carbon pools in rivers, reservoirs and lakes, with dissolved organic carbon (DOC) in DOM accounting for approximately 50% of the total carbon in inland water bodies. Thus, DOM plays an important role in the carbon cycle in terrestrial and aquatic ecosystems regionally and globally. To date, research on the ternary interaction of DOM, Fe and P is still scattered. This work characterized DOM in soil samples and sediments from rivers and reservoirs, analyzed the interception of OM, P and Fe by the construction of dammed reservoirs, and elucided the transformation of Fe and P together with DOM after the construction of dammed reservoirs. The results showed that interaction of DOM, Fe, P would be more likely form the Fe-DOM-P complexes rather than DOM-Fe-P complexes. Furthermore, Fe-DOM-P complexes would be re-dissolved, aggravating Fe, C and nutrient emissions under reduction of DOM. Thus, it is important for DOM monitoring at the interface of sediment-water to prevent the release of DOM, Fe, P together in reservoirs in a short time, which is also important for the preservation of carbon in the sediments for a long time. More mechanisms between DOM, Fe, P should be studied future in order to better understand the cycling of DOM, Fe and P together in the soils, rivers, reservoirs and even the oceans.

Technical Abstract: Dissolved organic matter (DOM) plays a major role in ecological systems, affecting the fate and transportation of iron (Fe) and phosphorus (P), especially in humic-rich lakes or reservoirs receiving large allochthonous DOM inputs from their watersheds. To better understand their geochemical cycling, soil and sediment samples were collected around a reservoir downstream of a typical temperate forest in Northeast China. The DOM fractions from these soils and inlet river and reservoir sediments were extracted and then characterized by spectroscopic techniques. Comparative characterization data showed that the DOM pool of the Reservoir was partly autochthonous partly from runoff or the deposition of terrestrial ecosystems in the upstream area. The correlation value between the concentrations of total Fe (TFe) and component tryptophan was 0.91 and significant (p<0.01). There was also a strong positive correlation between the concentrations of total P (TP) and tyrosine in the DOM (r=0.71, p<0.01, n=30). Organic P (Po) is the main composition of TP in the DOM, which was also significantly correlated with dissolved organic carbon (DOC) and the component tyrosine (p<0.01). The interaction among DOM and its Fe and P will promote the coordinated migration and transformation of these three from upstream soil to rivers’ sediments, and to reservoirs’ sediments. This is likely an important mechanism for DOM and nutrients by dam interception. Finally, this also effects on the bioavailability and cycling of DOM, Fe and P in the downstream rivers, and even the oceans, such as the component tryptophan and tyrosine related DOM.