Depth Distribution of Bacterial Production in a Stratified Lake with an Anoxic Hypolimnion
Depth Distribution of Bacterial Production in a Stratified Lake with an Anoxic Hypolimnion
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缺氧低度层状湖中细菌产生的深度分布
DOI：
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发表时间：
1986
影响因子：
4.4
通讯作者：
D. Kirchman
中科院分区：
文献类型：
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作者：
R. McDonough;R. Sanders;K. Porter;D. Kirchman
本研究的目的是确定细菌生物量和生产在分层湖泊的深度分布，并测试技术，以测量细菌生产在厌氧沃茨。细菌的丰度和掺入的[3 H]胸苷和[3 H]亮氨酸到蛋白质中是最高的metallamnion，在深度处，氧气第一次变得不可测量。相反，[3 H]胸腺嘧啶核苷掺入DNA是最高的表水层。掺入DNA/蛋白质的比率平均为2.2，0.49，和0.95的上层，上层和下层，分别。DNA中的低掺入不是由于与DNA分离程序相关的人为因素。在[~ 3 H]胸苷掺入DNA的部分约为40%的沃茨中，加入的[~ 3 H]DNA的回收率约为90%。至少有一些专性厌氧细菌能够同化胸苷，因为厌氧低水层沃茨的曝气基本上抑制胸苷的掺入。从总胸苷和亮氨酸掺入和分裂细胞的频率估计的细菌生产的深度配置文件都是相似的，最大的速率在metallamnion。然而，基于分裂细胞和亮氨酸掺入频率的细菌产量估计值通常显著高于基于胸苷掺入的估计值（使用文献中的转换因子），特别是在厌氧低层沃茨中。这些数据表明，胸苷的方法必须仔细检查，如果它是适用于低氧浓度的水生系统。研究结果还表明，好氧上层和厌氧下层之间的界面是细菌矿化和生物量产生的强烈场所，值得进一步研究。
The purpose of this study was to determine the depth distribution of bacterial biomass and production in a stratified lake and to test techniques to measure bacterial production in anaerobic waters. Bacterial abundance and incorporation of both [3H]thymidine and [3H]leucine into protein were highest in the metalimnion, at the depth at which oxygen first became unmeasurable. In contrast, [3H]thymidine incorporation into DNA was highest in the epilimnion. The ratios of incorporation into DNA/protein averaged 2.2, 0.49, and 0.95 for the epilimnion, metalimnion, and hypolimnion, respectively. Low incorporation into DNA was not due to artifacts associated with the DNA isolation procedure. Recovery of added [3H]DNA was about 90% in waters in which the portion of [3H]thymidine incorporation into DNA was about 40%. At least some obligate anaerobic bacteria were capable of assimilating thymidine since aeration of anaerobic hypolimnion waters substantially inhibited thymidine incorporation. The depth profile of bacterial production estimated from total thymidine and leucine incorporation and the frequency of dividing cells were all similar, with maximal rates in the metalimnion. However, estimates of bacterial production based on frequency of dividing cells and leucine incorporation were usually significantly higher than estimates based on thymidine incorporation (using conversion factors from the literature), especially in anaerobic hypolimnion waters. These data indicate that the thymidine approach must be examined carefully if it is to be applied to aquatic systems with low oxygen concentrations. Our results also indicate that the interface between the aerobic epilimnion and anaerobic hypolimnion is the site of intense bacterial mineralization and biomass production which deserves further study.