Walsby A E, Schanz F
School of Biological Sciences, University of Bristol, Bristol BS8 1UG, United Kingdom.
Institut für Pflanzenbiologie der Universitat Zürich, Limnologische Station, Seestrasse 187, CH-8802 Kilchberg, Switzerland.
New Phytol. 2002 Jun;154(3):671-687. doi: 10.1046/j.1469-8137.2002.00401.x.
• Analyses were made to determine which changes in a Lake Zürich population of Planktothrix rubescens were dependent on light- and temperature-dependent growth rates, and when growth was limited by the mixing depth. • Changes in vertical distribution of the cyanobacterium, determined weekly from August 1998 to September 1999, were related to growth increments calculated at 1-h time and 1-m depth intervals from values of irradiance, attenuance, temperature and biomass in the lake, using algorithms based on growth rates in culture. • Population biovolume varied annually from 1.2 to 120 cm m . During summer, modelled growth in the metalimnion matched the 50-fold population increase. Modelled growth exceeded the observed increase when Planktothrix was mixed into the nutrient-depleted epilimnion, suggesting nutrient limitation. The measured increase ceased when the mixed depth exceeded the critical depth for growth in autumn (Sverdrup's principle). Light limitation explained the gradual decrease of the population in winter. The steep decline in spring had other causes. • Population changes were largely determined by interactions of light and depth distribution; decreases in nutrient loading have had little impact on Planktothrix growth in Lake Zürich.
• 进行了分析，以确定苏黎世湖微红颤藻种群的哪些变化取决于光照和温度依赖的生长速率，以及生长何时受到混合深度的限制。• 1998年8月至1999年9月每周测定的蓝藻垂直分布变化，与利用基于培养物生长速率的算法，根据湖泊中辐照度、衰减度、温度和生物量的值，以1小时时间间隔和1米深度间隔计算的生长增量相关。• 种群生物体积每年在1.2至120立方厘米/平方米之间变化。在夏季，温跃层模拟的生长与种群增加50倍相匹配。当微红颤藻混合到营养耗尽的表层水体中时，模拟生长超过了观察到的增加量，表明存在营养限制。当秋季混合深度超过生长临界深度（斯韦德鲁普原理）时，测量到的增加量停止。光照限制解释了冬季种群的逐渐减少。春季的急剧下降有其他原因。• 种群变化在很大程度上由光照和深度分布的相互作用决定；营养负荷的减少对苏黎世湖微红颤藻的生长影响很小。
