Abundance of mesozooplankton in the western part of the Black Sea in spring 2002 during the National Monitoring Programme of the Bulgarian Institute of Oceanography

The dataset is based on samples collected in the spring of 2002 in the Western Black Sea in front of Bulgaria coast. The whole dataset is composed of 76 samples (from 27 stations of National Monitoring Grid) with data of mesozooplankton species composition abundance and biomass. Sampling on zooplankton was performed from bottom up to the surface at depths depending on water column stratification and the thermocline depth. Zooplankton samples were collected with vertical closing Juday net,diameter - 36cm, mesh size 150 µm. Tows were performed from surface down to bottom meters depths in discrete layers. Samples were preserved by a 4% formaldehyde sea water buffered solution. Sampling volume was estimated by multiplying the mouth area with the wire length. Mesozooplankton abundance: The collected material was analysed using the method of Domov (1959). Samples were brought to volume of 25-30 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 5 ml of sample was taken and poured in the counting chamber which is a rectangle form for taxomomic identification and count. Large (> 1 mm body length) and not abundant species were calculated in whole sample. Counting of organisms were made in the Dimov chamber under the stereomicroscope to the lowest taxon possible. Taxonomic identification was done at the Institute of Oceanology by Kremena Stefanova using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972). Taxon-specific abundance: The collected material was analysed using the method of Domov (1959). Samples were brought to volume of 25-30 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 5 ml of sample was taken and poured in the counting chamber which is a rectangle form for taxomomic identification and count. Copepods and Cladoceras were identified and enumerated; the other mesozooplankters were identified and enumerated at higher taxonomic level (commonly named as mesozooplankton groups). Large (> 1 mm body length) and not abundant species were calculated in whole sample. Counting and measuring of organisms were made in the Dimov chamber under the stereomicroscope to the lowest taxon possible. Taxonomic identification was done at the Institute of Oceanology by Kremena Stefanova using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972).本数据集基于2002年春季在保加利亚沿岸外的西黑海海域采集的样本构建。完整数据集包含76份样本（取自国家监测网格的27个站位），涵盖中型浮游动物（mesozooplankton）的物种组成、丰度及生物量数据。 浮游动物采样按照水柱分层与温跃层深度，从海底向上至表层进行。浮游动物样本采用垂直闭锁型裘氏网（Juday net）采集，该网直径36cm，网孔尺寸150 μm。采样采用分层拖网方式，从表层向下至各分层对应的海底深度进行。样本使用4%甲醛缓冲海水溶液进行固定。采样体积通过网口面积与拖曳绳长的乘积计算得到。 中型浮游动物丰度分析：采用Domov（1959）方法对采集的样品进行处理。根据浮游动物密度将样品定容至25~30 mL，并充分混匀，直至所有生物在样液中均匀随机分布。随后吸取5 mL样液注入矩形计数框，用于物种分类鉴定与个体计数。对于体长大于1 mm且丰度较低的物种，采用全样计数法进行统计。生物个体计数在实体显微镜下的迪莫夫计数框（Dimov chamber）中完成，鉴定至尽可能低的分类阶元。分类鉴定工作由克雷梅娜·斯特凡诺娃（Kremena Stefanova）在海洋学研究所完成，参考了相关分类学文献（Mordukhay-Boltovskoy, F.D.（主编），1968、1969、1972）。 类群特异性丰度分析：采用Domov（1959）方法处理采集的样品。根据浮游动物密度将样品定容至25~30 mL，并充分混匀，直至所有生物在样液中均匀随机分布。随后吸取5 mL样液注入矩形计数框，用于物种分类鉴定与个体计数。对桡足类（Copepods）与枝角类（Cladoceras）进行物种级鉴定与计数；其余中型浮游动物则按更高分类阶元（通常称为中型浮游动物类群）进行鉴定与计数。体长大于1 mm且丰度较低的物种采用全样计数法统计。生物个体的计数与测量在实体显微镜下的迪莫夫计数框中完成，鉴定至尽可能低的分类阶元。分类鉴定工作由克雷梅娜·斯特凡诺娃在海洋学研究所完成，参考了相关分类学文献（Mordukhay-Boltovskoy, F.D.（主编），1968、1969、1972）。