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Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds
Published on: September 26, 2017
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Trends in nutrients in the Changjiang River
Wentao Wu1, Junjie Wang2, Hao Wang3
1Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, PR China; Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, PR China.
The Science of the Total Environment
|February 21, 2023
Summary
Recent management of fertilizer use and pollution control in the Changjiang River Basin has altered nutrient dynamics. Declining phosphorus flux, driven by reduced fertilizer use, impacts coastal ecosystems and highlights global river trends.
Area of Science:
- Environmental Science
- Water Quality Management
- Riverine Biogeochemistry
Background:
- Understanding long-term nutrient dynamics in watersheds is crucial for effective water quality management.
- Anthropogenic activities significantly influence nutrient concentrations and fluxes in river systems.
Purpose of the Study:
- To investigate the impact of recent fertilizer management and pollution control on nutrient fluxes in the Changjiang River Basin.
- To analyze temporal trends of dissolved inorganic nitrogen (DIN), dissolved phosphorus (DIP), and dissolved silicate (DSi) from 1962 to the present.
Main Methods:
- Analysis of historical data from 1962 and recent survey data.
- Quantification of nutrient concentrations and fluxes (DIN, DIP, DSi) in different river reaches.
- Statistical analysis to determine drivers of nutrient flux changes, including fertilizer use and pollution control.
Main Results:
- DIN and DIP concentrations were higher downstream due to human activities, while DSi was evenly distributed.
- DIN and DIP fluxes increased from 1962-2000, DSi declined. Post-2000, DIN and DSi stabilized, DIP stabilized until the 2010s then decreased.
- Reduced fertilizer use explained 45% of DIP flux decline, with pollution control also significant. Nutrient ratios shifted, indicating silicon and phosphorus limitations.
Conclusions:
- A turning point in nutrient fluxes occurred in the 2010s, with DIN stabilizing and DIP declining.
- The observed decline in phosphorus flux in the Changjiang River mirrors global trends in other rivers.
- Continued basin nutrient management is essential for controlling coastal nutrient budgets and ecosystem stability.
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