Nitrogen distribution and ammonia release from the overlying water and sediments of Poyang Lake, China

• Published in: Environmental earth sciences Vol. 74; no. 1; pp. 771 - 778
• Main Authors: Yang, Zhiping, Wang, Lingqing, Liang, Tao, Huang, Manxiang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2015; Springer Nature B.V
• Subjects: Ammonia; ammonium nitrogen; Biogeosciences; Bottom water; Cores; denitrification; Earth and Environmental Science; Earth Sciences; Environmental Science and Engineering; freshwater; Freshwater lakes; Geochemistry; Geology; Hydrogeology; Hydrology/Water Resources; Karst; Lakes; Load distribution; nitrate nitrogen; Nitrification; Nitrogen; Original Article; Overflow; Rivers; sampling; Sediment samplers; Sediments; Spatial distribution; Surface water; Terrestrial Pollution; Vertical distribution; Water; Water analysis; Water depth; Water sampling; China; Yangtze River; Poyang Lake; China, People's Rep., Changjiang R; Ammonia release; Overlying water; Sediment; Nitrogen; Eutrophication
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-015-4081-8

Poyang Lake is the largest freshwater lake in China and is one of the two largest lakes connected with the Yangtze River. It is an overflow lake which absorbs and releases water seasonally. To evaluate the geochemical cycling of nitrogen (N) in Poyang Lake, the spatial distributions of ammonia nitrogen (NH₄ ⁺–N), nitrate nitrogen (NO₃ ⁻–N) and total nitrogen (TN) in sediments and overlying water were measured. The experimental results showed that the average concentrations of TN in the sediment samples, surface water, and bottom water samples from Poyang Lake were 1,107.375 mg kg⁻¹, 1.998 and 2.237 mg L⁻¹, respectively. The highest concentrations of TN were measured in the water and sediment obtained from the river tail region south of Poyang Lake, with decreasing pattern from south to north affected by the river input. The contribution of TN to the internal load played an important role on N distribution in the overlying water. The vertical distribution of TN in sediment cores of Poyang Lake showed a decreasing trend with depth. The NH₄ ⁺–N content in sediment cores initially decreased with depth and then increased slowly. The NO₃ ⁻–N content in sediment cores exhibited an inverse trend compared with that of NH₄ ⁺–N due to the influence of nitrification and denitrification processes. Release kinetic experiments of NH₄ ⁺–N demonstrated that the maximum NH₄ ⁺–N release rate occurred within first 5 min and reached 90–94 % of the maximum value within 0–10 min.