Abundance of mesozooplankton in the western part of the Black Sea in summer 1991 during the NATO Programme Hydroblack

The "Hydroblack91" dataset is based on samples collected in the summer of 1991 and covers part of North-Western in front of Romanian coast and Western Black Sea (Bulgarian coasts) (between 43°30' - 42°10' N latitude and 28°40'- 31°45' E longitude). Mesozooplankton sampling was undertaken at 20 stations. The whole dataset is composed of 72 samples with data of zooplankton species composition, abundance and biomass. Samples were collected in discrete layers 0-10, 0-20, 0-50, 10-25, 25-50, 50-100 and 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 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 Asen Konsulov 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 Asen Konsulov using the relevant taxonomic literature (Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972).‘Hydroblack91’数据集基于1991年夏季采集的样本，覆盖罗马尼亚海岸西北部近岸海域及西黑海（保加利亚海岸海域），地理范围介于北纬43°30′至42°10′、东经28°40′至31°45′之间。本研究共设置20个采样站位，整套数据集包含72份样本，涵盖浮游动物物种组成、丰度及生物量数据。样本按离散水层采集，包括0-10m、0-20m、0-50m、10-25m、25-50m、50-100m水层，以及根据水体层化结构和温跃层深度设置的从海底至表层的采样层。 浮游动物样本采用垂直封闭型Juday网（Juday Net）采集，网口直径36cm，网孔尺寸150μm。拖网作业按离散水层从表层向下至海底深度进行。样本使用4%甲醛海水缓冲溶液进行固定保存。采样体积通过网口面积与拖网绳长的乘积估算得到。 中型浮游动物（Mesozooplankton）丰度分析：采用Domov（1959）方法对采集样品进行处理。根据浮游动物密度将样品定容至25-30ml，充分搅拌直至所有生物在样品体积内随机分布。随后移取5ml样品至矩形计数框中，用于物种分类鉴定与计数。体型大于1mm且丰度较低的物种则对全样进行统计。在体视显微镜下使用Dimov计数框（Dimov Chamber）完成生物计数与测量，直至鉴定至最低分类阶元。物种分类鉴定由阿森·康苏洛夫（Asen Konsulov）在海洋学研究所完成，参考相关分类学文献（Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972）。 分类单元专属丰度：仍采用Domov（1959）方法处理采集样品，同样根据浮游动物密度将样品定容至25-30ml并充分混匀，确保生物在样品体积内随机分布。移取5ml样品至矩形计数框开展分类鉴定与计数。其中桡足类（Copepods）和枝角类（Cladoceras）需鉴定至物种水平并统计数量，其余中型浮游动物则按较高分类等级（通常称为中型浮游动物类群）进行鉴定与计数。体型大于1mm且丰度较低的物种同样对全样进行统计。在体视显微镜下使用Dimov计数框完成生物计数与测量，直至鉴定至最低分类阶元。物种分类鉴定由阿森·康苏洛夫在海洋学研究所完成，参考相关分类学文献（Mordukhay-Boltovskoy, F.D. (Ed.). 1968, 1969,1972）。