Pedrós-Alió C, Calderón-Paz JI, Gasol JM
Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC, Passeig Joan de Borbó s/n, 08039, Barcelona, Spain
FEMS Microbiol Ecol. 2000 Apr 1;32(2):157-165. doi: 10.1016/s0168-6496(00)00026-x.
Empirical models derived from literature data were used to compare the factors controlling prokaryotic abundance (PN) and prokaryotic heterotrophic production (PHP) in solar salterns. These empirical relationships were generated as multiple linear regressions with PN or PHP as dependent variables, while the independent variables were chosen to reflect the likely sources of organic matter, inorganic nutrients and temperature. These variables were then measured in solar salterns and the predictions made by the general relationships were compared to actual saltern values of PN and PHP. Saltern ponds of salinity higher than 100 per thousand departed significantly from the general relationships, while the ponds of salinity lower than 100 per thousand fitted well within the range of values predicted by the general models. The most likely explanation for the discrepancy of the former was the absence of bacterivory. This hypothesis was tested with data from other very different aquatic systems: karstic lakes with anaerobic hypolimnia and two marine areas in the Mediterranean and the Southern Ocean. The anoxic regions of karstic lakes departed significantly from the predictions of the general model, while the oxic layers conformed to the predictions. As in the case of salterns, this difference could be explained by the presence of significant predation in the oxic, but not in the anoxic, layers of these lakes. Finally, two marine areas with similar predation pressure on prokaryotes but very different impacts of viral lysis were tested. In all cases, PN values conformed to the predictions, suggesting that lysis due to viruses is not the main factor controlling PN in aquatic systems, which is more likely to be determined by the balance between bacterivory and resource supply. The present work also demonstrates the usefulness of empirical comparative analyses to generate predictions and to draw inferences on the functioning of microbial communities.
利用从文献数据得出的经验模型，比较控制太阳盐场中原核生物丰度（PN）和原核生物异养生产（PHP）的因素。这些经验关系通过以PN或PHP为因变量的多元线性回归生成，而自变量的选择是为了反映有机物质、无机养分和温度的可能来源。然后在太阳盐场中测量这些变量，并将一般关系所做的预测与PN和PHP的实际盐场值进行比较。盐度高于千分之一百的盐场池塘与一般关系有显著偏差，而盐度低于千分之一百的池塘则很好地符合一般模型预测的值范围。前者出现差异的最可能解释是缺乏噬菌作用。用来自其他非常不同的水生系统的数据对这一假设进行了检验：具有厌氧湖下层的岩溶湖以及地中海和南大洋的两个海域。岩溶湖的缺氧区域与一般模型的预测有显著偏差，而氧化层则符合预测。与盐场的情况一样，这种差异可以解释为这些湖泊的氧化层存在显著的捕食作用，而缺氧层则没有。最后，对两个对原核生物具有相似捕食压力但病毒裂解影响非常不同的海域进行了测试。在所有情况下，PN值都符合预测，这表明病毒引起的裂解不是控制水生系统中PN的主要因素，PN更可能由噬菌作用和资源供应之间的平衡决定。本研究还证明了经验比较分析在生成预测和推断微生物群落功能方面的有用性。
