Analysis of sterols in selected bloom-forming algae in China

• Published in: Harmful algae 2017-06, Vol.66, p.29-39
• Main Authors: Geng, Hui-Xia, Yu, Ren-Cheng, Chen, Zhen-Fan, Peng, Quan-Cai, Yan, Tian, Zhou, Ming-Jiang
• Format: Article
• Language: English
• Subjects: Biomarker; Biomarkers - analysis; China; Chlorophyta - chemistry; Diatoms - chemistry; Dinoflagellida - chemistry; Gas Chromatography-Mass Spectrometry; Harmful Algal Bloom; Harmful algal blooms; Sterol; Sterols - analysis; Stramenopiles - chemistry
• ISSN: 1568-9883; 1878-1470
• DOI: 10.1016/j.hal.2017.04.008

•Several bloom-forming algae in China were analyzed for sterols using GC–MS.•28-isofucosterol is a promising biomarker for green tide studies in Yellow Sea.•Dinosterol is a potential biomarker to represent bloom-forming dinoflagellates.•Brassicasterol is not a good indicator for most bloom-forming diatoms in China. Sterols, a group of stable lipid compounds, are often used as biomarkers in marine biogeochemical studies to indicate sources of organic matter. In this study, sterols in 13 species of major bloom-forming algae in China, which belong to Dinophyceae, Bacillariophyceae, Ulvophyceae, and Pelagophyceae, were analyzed with gas chromatography-mass spectrometry (GC–MS) to test their feasibility in representing different types of harmful algal blooms (HABs). It was found that (24Z)-stigmasta-5,24-dien-3β-ol (28-isofucosterol) was a major sterol component in green-tide forming macroalga Ulva prolifera. In bloom-forming dinoflagellates Alexandrium spp., Prorocentrum micans and Scrippsiella trochoidea, (22E)-4α,23-dimethyl-5α-ergost-22-en-3β-ol (dinosterol) was detected in addition to cholest-5-en-3β-ol (cholesterol), (22E)-ergosta-5,22-dien-3β-ol, (22E)-stigmasta-5,22-dien-3β-ol and other minor sterol components. In brown-tide forming pelagophyte Aureococcus anophagefferens, (24E)-24-propylcholesta-5,24-dien-3β-ol ((24E)-24-propylidenecholesterol) and (24Z)-24-propylcholesta-5,24-dien-3β-ol ((24Z)-24-propylidenecholesterol) were detected together with cholesterol, (22E)-stigmasta-5,22-dien-3β-ol, stigmast-5-en-3β-ol and campest-5-en-3β-ol. Among the selected bloom-forming diatoms, Chaetoceros sp. and Pseudo-nitzschia spp. only produced cholesterol, while Cylindrotheca closterium produced solely (22E)-ergosta-5,22-dien-3β-ol. Sterol content in four bloom-forming algal species correlates well with their biomass or abundance. It's proposed that 28-isofucosterol could serve as a promising biomarker for green algae in green-tide studies. Dinosterol and (24Z)-24-propylidenecholesterol can be used as potential biomarkers to represent bloom-forming dinoflagellates and pelagophytes, while (22E)-ergosta-5,22-dien-3β-ol is not a good indicator for diatoms.