文献类型： 外文期刊

作者： Yu, Juhua ¹ ; Zhong, Jicheng ² ; Zhang, Yushu ¹ ; Ding, Hong ¹ ; Chen, Chao ³ ; Zheng, Xiangzhou ¹ ; Xu, Mingxi ⁴ ; Zhang ¹ ;

作者机构： 1.Fujian Acad Agr Sci, Inst Soil & Fertilizer, Fuzhou 350013, Fujian, Peoples R China

2.Chinese Acad Sci, Nanjing Inst Geog & Limnol, State Key Lab Lake Sci & Environm, Nanjing 210008, Jiangsu, Peoples R China

3.China West Normal Univ, Coll Environm Sci & Engn, Nanchong 637009, Peoples R China

4.Nanjing Inst Vegetable Sci, Nanjing 210042, Jiangsu, Peoples R China

5.Nanjing Forestry Univ, Coinnovat Ctr Sustainable Forestry Southern China, Nanjing 210037, Jiangsu, Peoples R China

关键词： Aquatic macrophytes; DGT; Eutrophication; Lake restoration; Phosphorus; Sediment

期刊名称：JOURNAL OF SOILS AND SEDIMENTS （ 影响因子：3.308； 五年影响因子：3.586 ）

ISSN： 1439-0108

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收录情况： SCI

摘要： Purpose Aquatic vegetation serves an important structuring function in shallow freshwater ecosystems. Although increasing evidence indicates that sediment-associated phosphorus (P) is mobilized by aquatic macrophytes under P-deficient conditions, the influence of the holistic growth period of rooted macrophytes on transfer mechanism and bioavailability of sediment P around rhizosphere at millimeter scale remains unclear. Materials and methods In this present study, a 120-day batch intact sediment microcosm simulation was implemented to explore the effect of the whole Phragmites australis growth period on the stability and exchange of sediment P across critical micro-interfaces in lacustrine ecosystems. High-resolution dialysis peeper (HR-Peeper) was used to investigate the variations of pore water P in sediments around the P. australis rhizosphere and Zr-oxide diffusive gradients in thin-film (DGT) sampler was used to capture changes in the two-dimensional (2D) images of labile P over the whole growth period. Results and discussion Phosphorus fractionation showed a general decrease of total phosphorus (TP) and calcium-bound P (Ca-P), whereas an increase in iron-adsorbed P (Fe-P), loosely bound P (LS-P), and organic P (Org-P) was observed on day 120 compared to the values on day 0. Notably, the Ca-P content decreased by approximately 77%, while the Fe-P content increased by approximately 400%. Highly synchronous rises in P release flux and in the morphological characteristics of P. australis were the exponential function of incubation time. High-resolution data demonstrated that concentrations of soluble reactive P (SRP) and labile P concentrations in pore water were prominently enhanced by P. australis growth. Meanwhile, a top-down root-shaped patchy distribution pattern of labile P in the pore water was obviously stimulated over time. The reason for this phenomenon could be ascribed to remobilization of sediment mineral P by root organic exudates, as well as Fe-coupled accumulation of labile P due to oxygenation of Fe2+ followed by the formation of Fe plaques on the root surface within the more oxic rhizosphere. Conclusions The annual growth period of P. australis could persistently enhance the mobility of sediment P, converting it from a more inert status to a redox-sensitive species. Our findings highlight that remobilization of sediment-associated P by P. australis accounts for a significant portion of the P cycle in eutrophic lake ecosystems.