Abstract

Abundance and biomass of small photosynthetic flagellates (SPF; 3–10 µm), chlorophyll a concentration, and the contribution of SPF to total phytoplankton biomass at different stages of seasonal succession in ice and in surface water were studied in Kandalaksha Bay of the White Sea in September 2016 and February and July 2017. In summer, SPF biomass in the photic layer averaged 38.36 ± 9.77 mg C/m³, 2.22 ± 1.43 mg C/m³ in autumn, 2.6 ± 1.72 mg C/m³ in under-ice water, and 14.79 ± 11.25 mg C/m³ in ice. The contribution of SPF to total phytoplankton biomass depended on the season and ranged from 29 to 95%; the contribution of SPF to sympagic communities averaged 66%. The size structure of photosynthetic flagellates varied by seasons. Flagellates with a cell size of 6–10 µm dominated in summer plankton and in the ice. Flagellates with a cell size of 3–6 µm prevailed in autumn and in the under-ice water. The obtained data of SPF abundance showed higher values of the total phytoplankton biomass of the White Sea in the autumn–winter period compared with the estimates obtained previously. Applying the method of epifluorescence microscopy confirmed the idea that photosynthetic flagellates were the main producers in the winter period as well as in the summer when the biomass of planktonic algae with cell size exceeding 10 µm is low.

中文翻译：

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白海小型光合鞭毛：季节性动态及其在浮游生物和冰原中的作用

摘要

丰度和小光合鞭毛虫（SPF; 3-10微米）的生物质，叶绿素一个浓度，和SPF的在冰和地表水的季节性演替的不同阶段的贡献总浮游植物生物量在白海的坎达拉克沙湾进行了研究在2016年9月以及2月和2017年7月。在夏季，光层中的SPF生物量平均为38.36±9.77 mg C / m ³，秋季为2.22±1.43 mg C / m ³，在下层为2.6±1.72 mg C / m ³。冰水和14.79±11.25 mg C / m ³我好。SPF对浮游植物总生物量的贡献取决于季节，范围从29％到95％。SPF对症状性社区的贡献平均为66％。光合鞭毛的大小结构随季节而变化。夏季浮游生物和冰中，细胞大小为6–10 µm的鞭毛虫为主。秋季和冰下水域盛行的鞭毛大小为3–6 µm。与先前获得的估计值相比，获得的SPF丰度数据显示，秋冬季白海中浮游植物总生物量的值更高。应用落射荧光显微镜法证实了这样一种想法，即在冬季和夏季，当细胞大小超过10 µm的浮游藻类生物量较低时，光合鞭毛是主要的生产者。