Mikhailov Ivan S, Bukin Yurij S, Firsova Alena D, Petrova Darya P, Likhoshway Yelena V
Limnological Institute Siberian Branch of the Russian Academy of Sciences Irkutsk Russia.
Ecol Evol. 2025 Mar 19;15(3):e70856. doi: 10.1002/ece3.70856. eCollection 2025 Mar.
Phytoplankton is the basis of the food web and an indicator of environmental change in aquatic ecosystems. Phytoplankton assessment uses microscopy, which estimates the composition, absolute abundance and biomass of taxa, and metabarcoding, which estimates the composition, high richness and diversity, and relative abundance of taxa. Problems remain with the consistency of results from these two methods and the quantification of metabarcoding. Using 18S rRNA metabarcoding and microscopy we compared the relative or absolute abundance and biomass of phytoplankton taxa (class or genus/species) in the south basin of Lake Baikal in spring over 3 years. Absolute abundance/biomass of phytoplankton taxa estimated by metabarcoding was obtained by combining relative abundances of amplicon sequence variants (ASV produced by error-correcting method) derived from the V8-V9 region of 18S rRNA gene amplicon sequencing (primers were used that accurately represented the mean relative abundance of different microalgae) with total or class-specific abundance/biomass of phytoplankton estimated by light microscopy. Many Spearman correlations were found between relative (non- or clr-transformed) or absolute abundances/biomasses of the same phytoplankton classes or genus/species. Correlation coefficients were higher between absolute values than between relative values. Correlations were found between relative or absolute abundance/biomass, estimated by both methods, of the classes Bacillariophyceae, Coscinodiscophyceae, Mediophyceae, Chrysophyceae, Cryptophyceae, and Chlorophyceae, but not Dinophyceae and Trebouxiophyceae. Correlations were found between relative or absolute abundance/biomass of dominant species and ASVs of diatoms (, , ), Chrysophyceae (), and Cryptophyceae (). Thus, the consistency of the dynamics of the relative or absolute abundance/biomass of phytoplankton taxa estimated by the two methods was revealed. Absolute abundances/biomasses of taxa estimated by metabarcoding in combination with microscopy improve the accuracy of metabarcoding-based ecological assessment.
浮游植物是食物网的基础，也是水生生态系统环境变化的指标。浮游植物评估使用显微镜法，该方法可估计分类群的组成、绝对丰度和生物量，以及宏条形码技术，该技术可估计分类群的组成、高丰富度和多样性以及相对丰度。这两种方法的结果一致性以及宏条形码技术的定量方面仍然存在问题。我们使用18S rRNA宏条形码技术和显微镜法，比较了3年春季贝加尔湖南部流域浮游植物分类群（纲或属/种）的相对或绝对丰度及生物量。通过将18S rRNA基因扩增子测序V8-V9区域（使用能准确代表不同微藻平均相对丰度的引物）衍生的扩增子序列变体（由纠错方法产生的ASV）的相对丰度与光学显微镜估计的浮游植物总丰度或特定类别的丰度/生物量相结合，获得了通过宏条形码技术估计的浮游植物分类群的绝对丰度/生物量。在相同浮游植物纲或属/种的相对（未转换或clr转换）或绝对丰度/生物量之间发现了许多斯皮尔曼相关性。绝对值之间的相关系数高于相对值之间的相关系数。在硅藻纲、圆筛藻纲、中肋骨条藻纲、金藻纲、隐藻纲和绿藻纲的相对或绝对丰度/生物量之间发现了相关性，但在甲藻纲和小球藻纲中未发现相关性。在优势种的相对或绝对丰度/生物量与硅藻（、、）、金藻纲（）和隐藻纲（）的ASV之间发现了相关性。因此，揭示了两种方法估计的浮游植物分类群相对或绝对丰度/生物量动态的一致性。结合显微镜法通过宏条形码技术估计的分类群绝对丰度/生物量提高了基于宏条形码技术的生态评估的准确性。
