Neurobiology and Genetics, University of Würzburg, Biocentre, Theodor-Boveri-Institute, Am Hubland, 97074, Würzburg, Germany.
Section Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.
Sci Rep. 2024 Jul 23;14(1):16963. doi: 10.1038/s41598-024-67999-3.
Antarctic krill (Euphausia superba, hereafter krill) is a pelagic living crustacean and a key species in the Southern Ocean ecosystem. Krill builds up a huge biomass and its synchronized behavioral patterns, such as diel vertical migration (DVM), substantially impact ecosystem structure and carbon sequestration. However, the mechanistic basis of krill DVM is unknown and previous studies of krill behavior in the laboratory were challenged by complex behavior and large variability. Using a new experimental set-up, we recorded the swimming activity of individual wild-caught krill under light-dark cycles. Krill individuals exhibited differential phototactic responses to the light regime provided. However, using a new activity metric, we showed for the first time a consistent nocturnal increase in krill swimming activity in a controlled environment. Krill swimming activity in the new set-up was strongly synchronized with the light-dark cycle, similar to the diel vertical migration pattern of krill in the field when the krill were sampled for the experiment, demonstrated by hydroacoustic recordings. The new set-up presents a promising tool for investigating the mechanisms underlying krill behavioral patterns, which will increase our understanding of ecological interactions, the spatial distribution of populations, and their effects on biogeochemical cycles in the future.
南极磷虾（Euphausia superba，以下简称磷虾）是一种海洋浮游甲壳动物，是南大洋生态系统的关键物种。磷虾的生物量巨大，其同步的行为模式，如昼夜垂直迁移（DVM），对生态系统结构和碳封存有重大影响。然而，磷虾 DVM 的机制尚不清楚，以前在实验室中对磷虾行为的研究受到复杂行为和高度可变性的挑战。使用新的实验装置，我们记录了在光暗循环下野生磷虾个体的游泳活动。磷虾个体对提供的光照制度表现出不同的趋光反应。然而，我们使用新的活动指标，首次在受控环境中显示出磷虾游泳活动在夜间持续增加。在新装置中，磷虾的游泳活动与光暗循环强烈同步，与在野外采集实验用磷虾时的磷虾昼夜垂直迁移模式相似，这一点通过水声学记录得到了证明。新装置为研究磷虾行为模式的机制提供了一种有前途的工具，这将增加我们对生态相互作用、种群的空间分布及其对未来生物地球化学循环的影响的理解。
