Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir
Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir
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DOI：
10.1111/j.1462-2920.2006.01053.x
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发表时间：
2006-09-01
影响因子：
5.1
通讯作者：
Hahn, Martin W.
中科院分区：
文献类型：
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作者：
Simek, Karel;Hornak, Karel;Hahn, Martin W.
我们通过分析1997至2003年间在峡谷形状的里莫夫水库(捷克共和国)进行的8个现场操纵实验，研究了不同浮游细菌种群和异养纳米鞭毛虫(HNF)群落的净增长率与磷有效性的关系。将水样分级培养在采样点的透析袋中，或移植到磷限制不同的水库区域(可溶活性磷浓度范围-SRP，0.7-96 mU/g L(-1))。使用五种不同的rRNA靶向寡核苷酸探针，利用Monod动力学估计了探针定义的细菌群和HNF组合的净生长率，并与SRP相关联，得到了每个细菌群特有的生长速率常数。我们发现它们的最大生长速率之间存在着极显著的差异，而饱和常数的差异不显著。然而，后一种常量仅代表暂定估计，主要是因为在低现场SRP浓度时所用方法的灵敏度不够。有趣的是，在这些相同的实验中，除了一小群但丰富的贝塔蛋白细菌(R-BT065探针的靶标)外，HNF组合的生长速度明显快于所研究的任何细菌组。不同的生长能力对不同的细菌系统发育谱系的可能的生命策略的潜在的生态影响被讨论。
We investigated net growth rates of distinct bacterioplankton groups and heterotrophic nanoflagellate (HNF) communities in relation to phosphorus availability by analysing eight in situ manipulation experiments, conducted between 1997 and 2003, in the canyon-shaped Rimov reservoir (Czech Republic). Water samples were size-fractionated and incubated in dialysis bags at the sampling site or transplanted into an area of the reservoir, which differed in phosphorus limitation (range of soluble reactive phosphorus concentrations - SRP, 0.7-96 mu g l(-1)). Using five different rRNA-targeted oligonucleotide probes, net growth rates of the probe-defined bacterial groups and HNF assemblages were estimated and related to SRP using Monod kinetics, yielding growth rate constants specific for each bacterial group. We found highly significant differences among their maximum growth rates while insignificant differences were detected in the saturation constants. However, the latter constants represent only tentative estimates mainly due to insufficient sensitivity of the method used at low in situ SRP concentrations. Interestingly, in these same experiments HNF assemblages grew significantly faster than any bacterial group studied except for a small, but abundant cluster of Betaproteobacteria (targeted by the R-BT065 probe). Potential ecological implications of different growth capabilities for possible life strategies of different bacterial phylogenetic lineages are discussed.