Phosphate concentrations in lakes
Phosphate concentrations in lakes
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DOI：
10.1038/35017531
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发表时间：
2000-07-06
期刊：
影响因子：
64.8
通讯作者：
Schindler, DW
中科院分区：
文献类型：
--
作者：
Hudson, JJ;Taylor, WD;Schindler, DW
磷酸盐是限制许多淡水（1-3）和海洋环境（4-6）中微生物生产的重要营养素。磷限制沃茨中磷酸盐的实际浓度在很大程度上是未知的，因为常用的化学和放射化学技术高估了浓度（7，8）。在这里，使用一种新的稳态放射性生物测定法来调查一组不同的湖泊，我们报告的磷酸盐浓度的数量级低于估计的化学计量或经常使用的Rigler放射性生物测定。我们的研究结果，结合那些从文献中，表明微生物可以实现快速周转率在皮摩尔营养浓度。即使这些浓度比微型浮游生物群落的磷酸盐吸收量估计为饱和水平的一半的水平低两个数量级，也会发生这种情况。此外，虽然我们采样的湖泊中的总磷和可溶性活性磷的浓度增加的磷酸盐浓度，磷酸盐在总磷库中的比例从贫营养到富营养湖泊减少。这样的信息，揭示了我们在这里使用的磷酸盐测定，应该让我们解决有关的磷酸盐浓度的假设，可在水生系统中的浮游微生物。
Phosphate is an important nutrient that restricts microbial production in many freshwater(1-3) and marine environments(4-6). The actual concentration of phosphate in phosphorus-limited waters is largely unknown because commonly used chemical and radiochemical techniques overestimate the concentration(7,8). Here, using a new steady-state radiobioassay to survey a diverse set of lakes, we report phosphate concentrations in lakes that are orders of magnitude lower than estimates made spectrophotometrically or with the frequently used Rigler radiobioassay. Our results, combined with those from the literature, indicate that microbes can achieve rapid turnover rates at picomolar nutrient concentrations. This occurs even though these concentrations are about two orders of magnitude below the level where phosphate uptake is estimated to be half the saturation level for the picoplankton community. Also, while phosphate concentration increased with the concentration of total phosphorus and soluble reactive phosphorus in the lakes we sampled, the proportion of phosphate in the total phosphorus pool decreased from oligotrophic to eutrophic lakes. Such information, as revealed by the phosphate assay that we use here, should allow us to address hypotheses concerning the concentration of phosphate available to planktonic microorganisms in aquatic systems.