Phytoplankton Ecology and Physiology Group, Limnology Division, Faculty of Sciences, Universidad de la República, Montevideo, Uruguay.
FEMS Microbiol Ecol. 2011 Jul;77(1):1-16. doi: 10.1111/j.1574-6941.2011.01078.x. Epub 2011 Mar 17.
When phytoplankton growth in lakes is limited by the available phosphate, the external phosphate concentration fluctuates around a threshold value at which available energy is insufficient to drive phosphate incorporation into a polyphosphate pool. As a result, occasional increases in the external concentration are experienced by phytoplankton as a series of phosphate pulses. Based on [(32) P] phosphate uptake experiments with lake phytoplankton, we show that a community is able to process information about the experienced pattern of phosphate pulses via a complex regulation of the kinetic and energetic properties of cellular phosphate uptake systems. As a result, physiological adaptation to alterations of ambient phosphate concentration depends on the pattern of phosphate fluctuations to which the community had been exposed during its previous growth. In this process, the entire community exhibits coherent uptake behaviour with respect to a common threshold value. Thereby, different threshold values result from different antecedent pulse patterns, apparently unrestrained by the amount of previously stored phosphate. The coherent behaviour observed contradicts the basic assumptions of the competitive exclusion principle and provides an alternative perspective for explaining the paradoxical coexistence of many phytoplankton species.
当湖泊中的浮游植物生长受到可用磷酸盐的限制时，外部磷酸盐浓度会围绕一个阈值波动，在这个阈值下，可用能量不足以将磷酸盐纳入多磷酸盐库。因此，浮游植物偶尔会经历一系列磷酸盐脉冲，外部浓度会增加。基于对湖泊浮游植物进行的 [(32) P]磷酸盐吸收实验，我们表明，通过对细胞磷酸盐吸收系统的动力学和能量特性进行复杂的调节，群落能够处理有关经历的磷酸盐脉冲模式的信息。因此，对环境磷酸盐浓度变化的生理适应取决于群落在其先前生长过程中所经历的磷酸盐波动模式。在这个过程中，整个群落对于共同的阈值表现出一致的吸收行为。因此，不同的阈值来自于不同的先前脉冲模式，显然不受先前储存的磷酸盐数量的限制。观察到的一致行为与竞争排斥原理的基本假设相矛盾，并为解释许多浮游植物物种共存的悖论提供了另一种解释。
