Microscale chemical features of sediment-water interface in Hongfeng Lake
Microscale chemical features of sediment-water interface in Hongfeng Lake
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DOI：
10.1007/s12583-015-0618-8
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发表时间：
2016-06
影响因子：
3.3
通讯作者：
Jingfu Wang;Jing-an Chen;Z. Dai;Jian Li;Yang Xu;Jing Luo
中科院分区：
文献类型：
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作者：
Jingfu Wang;Jing-an Chen;Z. Dai;Jian Li;Yang Xu;Jing Luo
利用微传感器技术对红枫湖沉积物中O2、H2S、pH和氧化还原电位的微尺度分布进行了原位研究。结果表明，O2在表层3.9 mm内基本耗尽，H2S在表层6.0 mm处开始出现，在表层25 mm处达到最大值，有机质降解和硫酸盐还原可能是沉积物中H2S产生的主要途径。表层pH值迅速降低主要是由于有机质氧化过程中H+的释放。表层沉积物中Eh也急剧下降，可能是好氧区Fe、Mn氧化物与O2共存的结果。应用PROFILE程序对沉积物和扩散边界层中的O2梯度进行了模拟，模拟值与实际值吻合较好。结果表明，S1和S2站沉积物中O2的深度累积消耗速率分别为0.083和0.134 nmol·m−3·s− 1。此外，两个沉积物剖面中存在明显的DBL，S1厚度为1.2 mm，S2厚度为0.9 mm。O2在DBL中的扩散通量在S1中为67.13 nmol·m−2·s− 1，在S2中为88.54 nmol·m−2·s− 1。
In situ microscale distributions of O2, H2S, pH and redox potential in sediments of Hongfeng Lake, SW China, were investigated using the powerful microsensor technique. Our results show that O2was depleted within the top 3.9 mm in surface sediments, and H2S was subsequently detected at ∼6.0 mm depth, and reached its maximum concentrations at ∼25 mm. The degradation of organic matter and reduction of sulfate might be the major pathways of producing H2S in sediments. pH rapidly reduced in surface layers mainly due to H+ release in the oxidation of organic matter. Eh also decreased sharply in surface sediments, probabl indicating the coexistence of Fe and Mn oxides with O2in aerobic region. Furthermore, the programme of PROFILE was applied to model the O2gradient, and good fit was obtained between the simulative values and the factual values both in sediments and in the diffusive boundary layer (DBL). The results indicate that the depth-integrated O2consumption rates within sediments were 0.083 and 0.134 nmol·m−3·s−1in site S1 and site S2, respectively. In addition, there were distinct DBL in two sediment profiles, with 1.2 mm thickness in S1 and 0.9 mm thickness in S2. The diffusive fluxes of O2within the DBL were 67.13 nmol·m−2·s−1in S1 and 88.54 nmol·m−2·s−1in S2.