Phytoplankton sterol contents vary with temperature, phosphorus and silicate supply: a study on three freshwater species
Phytoplankton sterol contents vary with temperature, phosphorus and silicate supply: a study on three freshwater species
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DOI：
10.1080/09670262.2012.665484
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发表时间：
2012-05
影响因子：
2.4
通讯作者：
Maike Piepho;D. Martin‐Creuzburg;A. Wacker
中科院分区：
文献类型：
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作者：
Maike Piepho;D. Martin‐Creuzburg;A. Wacker
了解环境引起的浮游植物生物化学组成的变化在生理学研究和生态食物网研究中具有重要意义。在广泛的实验室实验中，我们测试了两种不同的温度（10°C和25°C）和磷供应梯度对三种淡水浮游植物物种四尾栅藻，卵形隐藻和小环藻的甾醇浓度的影响。硅藻C. Meneghiniana另外暴露于硅酸盐梯度。在两个单独的实验中，我们分析了（1）温度和磷供应的可能的交互作用和（2）四个磷水平和三个硅酸盐水平对藻甾醇浓度的影响。我们观察到，在25°C下，S. quadricauda和C. meneghiniana的生长受到温度的影响，而C.卵形的温度和磷供应对C. meneghiniana。这可能是由于一种甾醇（24-亚甲基胆甾醇）生物转化为另一种甾醇（22-二氢油菜甾醇）。增加磷的供应导致种特异性的影响甾醇浓度，即最佳曲线响应在S。quadricauda，C. meneghiniana中甾醇含量无明显变化;卵形的硅酸盐供应量对C. meneghiniana与磷素供应的效果相当。虽然我们没有观察到一个普遍的趋势，在三种浮游植物的测试，我们的结论是浮游植物的甾醇浓度受到温度和营养供应的强烈影响。互动效应指出，在评估环境引起的变化对浮游植物甾醇浓度的影响时，必须考虑到不止一个环境因素。
The understanding of environmentally induced changes in the biochemical composition of phytoplankton species is of great importance in both physiological studies and ecological food web research. In extensive laboratory experiments we tested the influence of two different temperatures (10°C and 25°C) and a phosphorus supply gradient on the sterol concentrations of the three freshwater phytoplankton species Scenedesmus quadricauda, Cryptomonas ovata and Cyclotella meneghiniana. The diatom C. meneghiniana was additionally exposed to a silicate gradient. In two separate experiments we analysed (1) possible interactive effects of temperature and phosphorus supply and (2) the effect of four phosphorus levels and three silicate levels on algal sterol concentrations. We observed that sterol concentrations were higher at 25°C than at 10°C in S. quadricauda and C. meneghiniana, but were not affected by temperature in C. ovata. Interactive effects of temperature and phosphorus supply on sterol concentrations were found in C. meneghiniana. This presumably was due to the bioconversion of one sterol (24-methylenecholesterol) into another (22-dihydrobrassicasterol). Increasing phosphorus supply resulted in species-specific effects on sterol concentrations, viz. an optimum curve response in S. quadricauda, a saturation curve response in C. meneghiniana and no change in sterol concentration in C. ovata. Effects of silicate supply on the sterols of C. meneghiniana equalled the effects of phosphorus supply. Albeit we did not observe a general trend in the three phytoplankton species tested, we conclude that sterol concentrations of phytoplankton are strongly affected by temperature and nutrient supply. Interactive effects point out the importance of taking into account more than just one environmental factor when assessing the effects of environmentally induced changes on phytoplankton sterol concentrations.