淡水和海水环境下沉积物搬运过程碳释放通量的模拟研究

基于室内物理模拟实验, 对长江沉积物进行淡水和海水环境下沉积物搬运过程碳释放通量实验模拟。结果表明, 模拟实验初期, 淡水和海水均为大气CO₂的源, 但淡水CO₂释放通量略高于海水;淡水、海水两种环境下, CH₄释放通量均较小, 为弱释放-弱吸收过程。对两种环境下碳通量对比研究发现,Eh 值可能是造成淡水和海水环境下CO₂通量差别的主要原因, 而pH 值可能对CO₂通量差别的影响较小。两种环境下温室气体通量差别的具体原因仍需进一步研究。通过模拟对比试验, 旨在为系统地认识长江流域水库的温室效应与减排提供科学依据, 为我国清洁水电能源发展提供理论参考。

A simulation of carbon fluxes from sediment transportation in freshwater and seawater

Using laboratory physical simulation experiment we investigated the carbon release fluxes in the Changjiang River sediment in the seawater environment and the freshwater environment, respectively. The results showed that the atmospheric CO₂ came from freshwater and seawater, and the release fluxes of CO₂ in freshwater were higher than that in seawater. In both these two environments, the release fluxes of CH₄ were small, at the same time, the uptake fluxes of CH₄ were small, too. By comparison of the carbon fluxes in these two environments, we found that the variation of Eh values was possibly a most important factor attributing to the difference in fluxes of CO₂. On the contrary, the variation of pH values possibly had little influence on the difference of CO₂ fluxes. The concrete reasons which caused the difference in greenhouse gas fluxes in these two environments should be further studied. The results of laboratory physical simulation experiment, are very helpful to understanding of the greenhouse effect of the reservoir in the Changjiang River basin and provide a scientific basis for emission reduction, and provide theoretical reference for clean water and electricity energy development in China.