Seasonal change in microbial sulfur cycling in monomictic Lake Fukami‐ike, Japan
Seasonal change in microbial sulfur cycling in monomictic Lake Fukami‐ike, Japan
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DOI：
10.4319/lo.2012.57.4.0974
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发表时间：
2012-07
影响因子：
4.5
通讯作者：
M. Nakagawa;Y. Ueno;S. Hattori;M. Umemura;A. Yagi;K. Takai;K. Koba;Y. Sasaki;Akiko Makabe;N. Yoshida
中科院分区：
文献类型：
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作者：
M. Nakagawa;Y. Ueno;S. Hattori;M. Umemura;A. Yagi;K. Takai;K. Koba;Y. Sasaki;Akiko Makabe;N. Yoshida
研究了日本单一湖泊深上湖的硫收支和硫循环过程的季节变化。硫同位素质量平衡表明，地下水为主要硫源（δ34S =‐15.0‰）。硫酸盐流入被微生物硫酸盐还原约20%，并沉积为硫化物（δ34S =‐22.2‰；34 kmol yr−1）；其余部分从流出通道出口（δ34S =‐12.6‰）。在水体中，微生物学分析显示，绿色硫细菌在缺氧层中占90%以上的种群。每个深度的硫酸盐浓度每月下降表明，由于硫酸盐浓度低（< 600µmol L−1），硫酸盐还原在水柱内作为一级反应进行。根据4 ~ 8月硫酸盐和硫化物的同位素和浓度数据，估计硫酸盐还原的同位素分馏系数为0.980。数值模拟表明，在4 - 8月，光养硫化物氧化的相对贡献比硫酸盐还原慢50倍以上，而在10 - 11月，由于硫酸盐条件较低（< 300µmol L−1），硫化物氧化的相对贡献比硫酸盐还原高2倍以上。在单一湖泊中，硫酸盐浓度是控制硫酸盐还原和光营养硫化物氧化相对贡献的因素，这与在永久分层湖泊中观察到的结果形成对比。
Sulfur budgets and seasonal progression of sulfur cycling processes were investigated in Lake Fukami‐ike, a small monomictic lake in Japan. The sulfur isotopic mass balance shows that the main sulfur source is groundwater inflow (δ34S = ‐15.0‰). The sulfate influx is approximately 20% reduced by microbial sulfate reduction and deposited as sulfide (δ34S = ‐22.2‰; 34 kmol yr−1); the remaining exits from the outflow channel (δ34S = ‐12.6‰). In the water column, microbiological analyses reveal that green sulfur bacteria dominate more than 90% of the population in the anoxic layer. A monthly decrease in sulfate concentration at each depth indicates that sulfate reduction proceeds within the water column as a first‐order reaction because of low sulfate concentration (< 600 µmol L−1). The isotopic fractionation factor of sulfate reduction is estimated to be 0.980 by the isotopic and concentration data of sulfate and sulfide from April to August. Numerical simulation indicates that the relative contribution of phototrophic sulfide oxidation is over 50 times slower than sulfate reduction from April to August but over two times higher from October to November because of lower sulfate conditions (< 300 µmol L−1). Sulfate concentration is the factor for controlling the relative contribution of sulfate reduction and phototrophic sulfide oxidation in monomictic lakes, which contrasts with that observed in permanently stratified lakes.