(Table 4) Mesozoolpankton abundance and biomass and relative percentage of key zooplankton groups along the Bulgarian coast, Black Sea

Results of studies during Project of an international expedition onboard R/V Vladimir Parshin in September-October 2005 are presented. Intensive development of Bacillariophyceae and Dynophyceae was recorded in coastal waters of Bulgaria, Turkey, and in the Danube River delta during period of investigations. Increase in algae population was accompanied by rising of chlorophyll a concentration up to 2.0-5.5 µg/l. In the deep water region it did not exceed 0.5 µg/l. Phytoplankton growth rate in the surface water layer varied from 0.1 to 1.0 1/day. This parameter and NO2+NO3 concentration, as well as the silicon concentration were correlative, as was described by the Michaelis-Menten equation. Phytoplankton growth was affected by basic nutrients. Zooplankton grazing varied from 0.10 to 0.69 1/day and average values in different regions varied by 1.5 times. Microalgae size range is one of major factors of grazing regulation. Rate of phytoplankton consumption was decreasing with increasing the largest diatom Pseudosolenia calcar-avis impact on total biomass of nano- and microphytoplankton.本研究展示了2005年9-10月搭载弗拉基米尔·帕尔申号（R/V Vladimir Parshin）考察船开展的国际科考项目中的研究成果。本研究期间，在保加利亚、土耳其近岸海域及多瑙河三角洲水域均记录到硅藻门（Bacillariophyceae）与甲藻门（Dynophyceae）的大规模增殖。藻类种群数量的增长伴随叶绿素a浓度升高，最高可达2.0~5.5 µg/L；而在深水区域，叶绿素a浓度未超过0.5 µg/L。表层水体的浮游植物（Phytoplankton）生长速率介于0.1~1.0 d⁻¹。该参数与亚硝酸盐+硝酸盐（NO₂+NO₃）浓度及硅浓度均呈相关关系，符合米氏方程（Michaelis-Menten equation）的描述。浮游植物生长受到基础营养盐的调控。浮游动物（Zooplankton）的摄食速率介于0.10~0.69 d⁻¹，不同海域的平均摄食速率相差可达1.5倍。微型藻类（Microalgae）的粒径范围是调控浮游动物牧食的核心影响因素之一。随着大型硅藻伪长管藻（Pseudosolenia calcar-avis）对纳米浮游植物与微型浮游植物总生物量的贡献占比提升，浮游植物的被摄食速率呈下降趋势。