Vertical day-night distribution of the salp Soestia zonaria in the temperate Northeast Atlantic and the Southwest Pacific over the Chatham Rise

Although the oceanic widespread pelagic tunicate Soestia zonaria has been studied for more than a century, little ecological information exists. Soestia primarily occurs in tropical to warm-temperate regions. Soestia specimens were collected between 2015 and 2021 during three research expeditions (EXPORTS cruise to the Northeast Atlantic and TAN1516 and TAN1810 over the Chatham Rise, New Zealand) using MOCNESS-1 net and large midwater trawl with maximum sampling depths of 1000 m. More than 530 Soestia specimens (oral-atrial length: 4–68 mm) were analysed for their vertical distribution, i.e., weighted mean depths (WMD) during the day and night, and migration distance.

尽管广布于大洋的浮游被囊动物索氏带被囊虫（Soestia zonaria）已被研究逾一个世纪，但目前关于其生态的相关资料仍较为匮乏。该物种主要栖息于热带至暖温带海域。研究样本于2015至2021年间通过三次科考航次采集获得：东北大西洋EXPORTS航次，以及新西兰查塔姆海隆海域的TAN1516、TAN1810航次；采样工具为MOCNESS-1型网具与最大采样深度可达1000米的大型中层拖网。本研究共分析了530余件该物种标本（口-围鳃腔体长范围4~68 mm），并对其昼夜垂直分布特征——即日间与夜间的加权平均深度（weighted mean depths, WMD）——以及垂直迁移距离展开了分析。