Mesozooplankton abundances at timeseries station Helgoland Roads, in 2021

Samples to detemine zooplankton abundance were collected as part of the Helgoland Roads long-term data series in 2021. Zooplankton were sampled at the "Kabeltonne" site (54°11.3′N, 7°54.0′E) using an oblique haul with a 150µm hand net (Apstein, Hydrobios, Kiel) and preserved in 4% formaldehyde (buffered with Borax) to allow for storage and later examination. Sampling volume was calculated with a mechanic flowmeter (Hydrobios, Kiel). Samples were counted either as whole or as subsamples depending on the density. However, at least 60 individuals of each key species were counted per subsample to ensure counting of a representative part of the sample. Species were identified to the lowest possible taxonomic level using a stereomicroscope (Leica M205C). If identification to the species level was not possible, the next identifiable taxonomic category was assigned.

2021年，作为黑尔戈兰航道（Helgoland Roads）长期数据序列的组成部分，研究人员采集了用于测定浮游动物丰度的样本。浮游动物样本采集于‘Kabeltonne’站点（北纬54°11.3′，东经7°54.0′）：研究人员使用孔径150μm的手持网（Apstein、Hydrobios，基尔产）进行斜拖采样，随后将样本置于4%硼砂缓冲甲醛溶液中固定，以便后续储存与镜检分析。采样体积通过机械式流量计（Hydrobios，基尔产）测算得到。根据样本密度，采用全样计数或子样本计数两种方式进行样本计数。但为确保子样本的代表性，每个子样本中每个关键物种至少需计数60个个体。研究人员使用体视显微镜（Leica M205C）对物种进行分类鉴定，尽可能将其鉴定至最低可行的分类阶元。若无法将样本鉴定至物种水平，则将其划归至可识别的次一级分类阶元。