Dissolved oxygen stratification changes nitrogen speciation and transformation in a stratified lake
Xiaoxuan Su1,2, Qiang He3,4, Yufeng Mao1,2
1Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China.
Environmental Science and Pollution Research International
|December 1, 2018
Summary
Dissolved oxygen stratification significantly alters nitrogen cycling in lakes. This study reveals distinct nitrogen behaviors in different water layers, impacting lake management strategies.
Area of Science:
- Environmental Science
- Limnology
- Biogeochemistry
Background:
- Dissolved oxygen (DO) stratification is a common lake phenomenon.
- Its precise impact on nitrogen (N) speciation and transformation across water layers remains unclear.
Purpose of the Study:
- To investigate how DO stratification affects N species and transformation in distinct lake water layers.
- To understand the implications for lake ecosystem functioning and management.
Main Methods:
- High-frequency sampling during summer in Longjing Lake, China.
- Analysis of N speciation and transformation in stratified water columns (epilimnion, oxycline, hypolimnion).
Main Results:
- DO stratification created distinct epilimnion, oxycline, and hypolimnion layers.
- The oxycline showed the highest N removal capacity (714 kg N).
- Hypolimnion nitrogen was dominated by ammonium (NH4+), with significant sediment contribution (85%) and N2O accumulation (8 kg, ~70% of total).
Conclusions:
- DO stratification drives significant shifts in N speciation and transformation across lake depths.
- These findings are crucial for developing targeted lake management and protection strategies based on water depth.
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