Sea-ice protist (including ice algae) abundance and biodiversity data from ice coring at the main coring sites (MCS_FYI and MCS_SYI) and ridges during MOSAiC legs 2 to 4 in 2019/2020

The data has been collected during the expedition "Multidisciplinary drifting Observatory for the Study of Arctic Climate" (MOSAiC) from September 2019 to September 2020 on research vessel Polarstern. The dataset contains abundance of sea ice protists, including ice algae (autotrophic) and protozoa (heterotrophic). Protists were identified and counted with light microscopy using the Utermöhl method and the result are given as cells per liter (cells/L) called Abundance. Sea ice samples were collected with a 9 cm diameter ice corer (Kovacs Enterprise) from both level and ridge ice. The samples were collected from the bottom part of the ice core and generally sectioned from 0-3 cm, 3-10 cm and in 10 cm intervals thereafter. With some exceptions, ice core sections were melted in filtered sea water at 4°C. Melted samples were preserved using Lugol-formaldehyde mixture with a few drops of acidic Lugol solution and hexamethylenetetramine-buffered formalin at a final concentrations of 1%.

本数据集采集于2019年9月至2020年9月期间开展的“北极气候研究多学科漂流观测站”（Multidisciplinary drifting Observatory for the Study of Arctic Climate, MOSAiC）科考航次，所有采集工作均在“极星号”（Polarstern）科考船上完成。数据集包含丰富的海冰原生生物（sea ice protists），涵盖自养型冰藻（ice algae）与异养型原生动物（protozoa）两类。科研人员采用乌特莫尔法（Utermöhl method）结合光学显微技术（light microscopy）对原生生物进行鉴定与计数，结果以每升细胞数（cells/L）为单位，记为丰度（Abundance）。海冰样本采用直径9厘米的科瓦奇企业型（Kovacs Enterprise）冰钻（ice corer）采集，采样覆盖平整冰与脊状冰两种海冰类型。样本取自冰芯底部，通常按0~3厘米、3~10厘米及后续以10厘米为间隔进行分段处理。除少数例外情况外，所有冰芯分段均在4℃的过滤海水（filtered sea water）中完成融化。融化后的样本采用含少量酸性卢戈氏溶液（acidic Lugol solution）与终浓度1%六亚甲基四胺缓冲福尔马林（hexamethylenetetramine-buffered formalin）的卢戈氏甲醛混合液（Lugol-formaldehyde mixture）进行固定保存。