Mesozooplankton biomass during Mikhail Lomonosov cruise ML25, Part II

Mesozooplankton was sampled by open-closing JUDAY net with a 36 cm ring diameter and mesh size of 125 µm. The open-closing mechanism used was the Nansen mechanical lock system allowing nets to be vertically towed through standard depths (0-10, 10-25, 25-50, 50-100, 100-200, 200-300, 300-500 m) and closed at the upper depth level. Depth of tow was evaluated by wire paid out and the angle of wire inclination. The 10-20 ml samples were preserved in 3-4% buffered formaldehyde and processed on return to the laboratory. All of copepods were identified to genus level, other taxonomic groups - to type, class, order and family levels.

本研究采用网口直径36厘米、网目尺寸125微米的开闭式JUDAY网采集中型浮游动物（Mesozooplankton）。该网具搭载南森机械锁定式开闭机构，可沿垂直方向在预设水层（0~10米、10~25米、25~50米、50~100米、100~200米、200~300米、300~500米）开展拖网，并于对应水层的上层边界处闭合。拖网的实际作业深度通过放出的钢缆长度及钢缆倾斜角进行测算。采集得到的10~20毫升样品经3%~4%缓冲甲醛溶液固定保存，并在返回实验室后完成后续处理。所有桡足类（Copepods）均被鉴定至属级分类单元，其余分类类群则分别鉴定至型、纲、目及科级分类单元。