Effects Of Short-Term Aerobic Conditions On Phosphorus Mobility In Sediments

Abstract

In this study, the effects of short-term aerobic conditions on phosphorus (P) mobility in sediment were investigated in the eutrophic lakes. To accomplish this, an indoor cultivation system was established and short-term cultivation (3, 8 and 15 days) was conducted under control and aerobic treatments. High-resolution diffusive gradients in thin films (DGT) and dialysis (HR-Peeper) techniques were used to determine the mobility patterns of P in sediments. The results showed that: (1) Aerobic treatment significantly increased oxygen concentrations (maximum 17.1%) in overlying water within 15 days, with no significant effects on sediment oxygen penetration depth or redox potential. Additionally, aerobic treatment inhibited soluble reactive phosphorus (SRP) and DGT-labile P release from sediment to overlying water. (2) Aerobic treatment decreased the pore water SRP and soluble Fe(II) on day 3 with no impact on sediment SRP/DGT-labile P and soluble/DGT-labile Fe on day 8 and 15. (3) Model simulation using DGT Induced Fluxes in Sediments (DIFS) showed that the pore water SRP replenishment ability of sediment particle P was lower in the aerobic group than the control group, and the sediment system equilibration time was elongated after pore water SRP decreased in the aerobic group on day 3. (4) On day 3, SRP and soluble Fe(II), DGT-labile P and DGT-labile Fe showed significant positive correlations (r > 0.888, p < 0.001), indicating that reduced pore water SRP concentration was related to decreased pore water soluble Fe(II).

Key words:

• Aerobic
• Sediments
• Phosphorus
• Iron
• Diffusive gradients in thin films

Acknowledgments

This work was supported by the National Key R&D Program of China (2017YFC0405205), National Natural Science Foundation of China (Nos. 41701568, 41301531 and 51279060), Key Research Program of Frontier Sciences, Chinese Academy of Sciences (QYZDJSSWDQC008), and the “One-Three-Five” Strategic Planning of Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (NIGLAS2017GH04). We thank Jeremy Kamen, MSc, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.

Notes on contributors

Wenming Yan is an associate professor in Hohai University, China. She studies environmental hydrology and water environment protection in shallow lakes.

Ling Liu is a professor in Hohai University, China. She is an ecologist who studies the aquatic biological diversity in rivers and lakes.

Tingfeng Wu is an associate professor in Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China. He studies environmental hydrodynamics in shallow lakes.

Lanlan Song is an associate professor in Hohai University, China. She is good at ecological environment assessment.

Han Wang is an MSc student. China. He studies ecological water conservancy.

Zhanjin Lu is an engineer in Chongqing Research Institute of Coal Science and Industry Group Co., Ltd., China. He studies water resources and water environment.

Botao Li is an MSc student. China. He studies the structure characteristics of plankton community in the rivers.

Yan Zhu is an MSc student. China. She studies the structure characteristics of plankton community in the rivers.