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Updated: Jul 17, 2026

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
Dynamic phosphorus budget for lake-watershed ecosystems.
Yong Liu1, Huai-Cheng Guo, Li-Jing Wang
1College of Environmental Sciences, Peking University, Beijing 100871, China.
Excess phosphorus (P) loading from agriculture and sewage is driving eutrophication in China's Qionghai Lake. Urgent management strategies are needed to reduce P inputs and protect the lake ecosystem.
Area of Science:
- Environmental Science
- Ecology
- Water Resource Management
Background:
- Lake eutrophication due to phosphorus (P) loading is a significant ecological issue in China.
- Excess P originates from both point sources (PS) and nonpoint sources (NPS), impacting water bodies like Qionghai Lake.
Purpose of the Study:
- To develop and apply a phosphorus budget model using material flow analysis (MFA) and system dynamics (SD) for the Qionghai Lake watershed.
- To analyze the changes in P budget dynamics influenced by watershed processes and socio-economic development.
Main Methods:
- Implemented a combined Material Flow Analysis (MFA) and System Dynamics (SD) approach to model P transport and budget.
- Quantified P inflows (fertilizer, soil loss, sewage, atmospheric deposition) and outflows (hydrologic export, water use, harvesting) from 1988 to 2015.
- Incorporated internal P recycling processes within the lake-watershed ecosystem.
Main Results:
- Total P inflows to Lake Qionghai significantly increased from 35.65 to 78.73 t/a between 1988 and 2015, leading to elevated P concentrations.
- In 2015, agricultural runoff (70.60%) and domestic sewage (17.27%) were the primary contributors to the total P load.
- These increases are directly linked to rapid socio-economic development and urbanization in the watershed.
Conclusions:
- The MFA-SD model effectively captures P dynamics in the lake-watershed system.
- Urgent implementation of management programs to reduce P inputs is crucial for restoring and maintaining the ecosystem health of Qionghai Lake.
- Addressing agricultural P losses and domestic sewage is key to mitigating eutrophication.
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