Institute of Biochemistry and Biology, Theoretical Aquatic Ecology, University of Potsdam, Potsdam, Germany.
PLoS One. 2010 Dec 31;5(12):e15828. doi: 10.1371/journal.pone.0015828.
Sterol profiles of microalgae and their change with environmental conditions are of great interest in ecological food web research and taxonomic studies alike. Here, we investigated effects of light intensity and phosphorus supply on the sterol content of phytoplankton and assessed potential interactive effects of these important environmental factors on the sterol composition of algae. We identified sterol contents of four common phytoplankton genera, Scenedesmus, Chlamydomonas, Cryptomonas and Cyclotella, and analysed the change in sterol content with varying light intensities in both a high-phosphorus and a low-phosphorus approach. Sterol contents increased significantly with increasing light in three out of four species. Phosphorus-limitation reversed the change of sterol content with light intensity, i.e., sterol content decreased with increasing light at low phosphorus supply. Generally sterol contents were lower in low-phosphorus cultures. In conclusion, both light and phosphorus conditions strongly affect the sterol composition of algae and hence should be considered in ecological and taxonomic studies investigating the biochemical composition of algae. Data suggest a possible sterol limitation of growth and reproduction of herbivorous crustacean zooplankton during summer when high light intensities and low phosphorus supply decrease sterol contents of algae.
微藻的甾醇特征及其随环境条件的变化在生态食物网研究和分类学研究中都具有重要意义。在这里，我们研究了光照强度和磷供应对浮游植物甾醇含量的影响，并评估了这些重要环境因素对藻类甾醇组成的潜在相互作用。我们确定了四种常见浮游植物属（Scenedesmus、Chlamydomonas、Cryptomonas 和 Cyclotella）的甾醇含量，并分析了在高磷和低磷两种方法下，不同光照强度下甾醇含量的变化。在四种物种中的三种中，甾醇含量随着光照强度的增加而显著增加。磷限制改变了甾醇含量与光照强度的关系，即在低磷供应下，甾醇含量随光照强度的增加而降低。一般来说，低磷培养物中的甾醇含量较低。总之，光照和磷条件强烈影响藻类的甾醇组成，因此在研究藻类生化组成的生态和分类学研究中应予以考虑。数据表明，在夏季，高光照强度和低磷供应降低藻类甾醇含量时，可能会限制草食性桡足类浮游动物的生长和繁殖。
