Fluorescent dissolved organic matter facilitates the phytoavailability of copper in the coastal wetlands influenced by artificial topography

• Published in: The Science of the total environment 2021-10, Vol.790, p.147855-147855, Article 147855
• Main Authors: Hong, Hualong, Wu, Shengjie, Wang, Qiang, Dai, Minyue, Qian, Lu, Zhu, Heng, Li, Junwei, Zhang, Jie, Liu, Jingchun, Li, Jian, Lu, Haoliang, Yan, Chongling
• Format: Article
• Language: English
• Subjects: Artificial topography; Element behavior; Litter trapping; Organic carbon accumulation; Wetland plants
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.147855

Dissolved organic matter (DOM) is a crucial driver in ecosystem services and a central part of the carbon transport and biological cycle in land-sea interaction. DOM exhibits characteristic environmental behavior in the coastal zone, but its sustainability is affected by expanding artificial topography (AT) construction. It requires combining analyses on AT-induced response of field fluorescent DOM (fDOM) and its quenching pattern under metal-complexation. Herein, we conducted systemic investigations into the spatiotemporal dynamics of fDOM compositions with further in-lab verification to study its Cu-binding capacity. We detected three humid-like fDOM components sensitive to AT. The total fDOM intensity was positively correlated with low molecular weight organic acid (LMWOA) extractable Cu and the Cu pools in above-ground biomass. The enriched fDOM serves as an ecological engineer by increasing the Cu mobility, confirmed by an in-lab fluorescence titration. The application of LMWOA greatly enhanced the intensity of one fDOM component, elevated its conditional stability constant, and decreased its quenched proportion, implying that LMWOA might extract part of Cu from fDOM complexation. The present work provides an “fDOM-LMWOA pump” explanation to suggest that fDOM is a novel ecological regulator on vegetation growth under the AT-induced matter accumulation. [Display omitted] •The fDOM changed spatiotemporally in an artificial topography (AT)-impacted wetland.•The fDOM's pattern was correlated with Cu supply of Spartina alterniflora.•Enriched fDOM in AT-impacted wetlands could chelate Cu and increase its mobility.•The fDOM could be a novel eco-regulator for Cu supply in the AT-impacted wetlands.