ABSTRACT: In the eastern Bering Sea, lipid-rich copepods in the genus Calanus help to sustain productive fisheries and efficient energy flow through the ecosystem. In summer and autumn, Calanus populations consist primarily of stage C5 copepodites that are storing lipids and preparing for dormancy (diapause). We collected Calanus C5 copepodites from the eastern Bering Sea shelf in early autumn of 2015 and examined whether Calanus species composition, morphometric characteristics, and lipid-related gene expression varied along a north-south gradient. The sampled area exhibited marked differences in temperature, chl a, and Calanus abundance. However, the Calanus population was surprisingly homogeneous, composed almost entirely of C. glacialis, with no evidence for latitudinal trends in prosome size, oil sac fullness, or lipid-related gene expression. Rather than a latitudinal gradient, we found that C. glacialis from 1 southern station near the Pribilof Islands were larger and exhibited lower oil sac fullness and higher expression of lipid storage genes. Gene expression changes across stations were small relative to large shifts associated with shipboard feeding experiments. The similar characteristics of C. glacialis across stations imply that most of the C5 copepodites had experienced favorable growth conditions regardless of their latitudinal location. It remains unknown how environmental conditions affect C. glacialis physiology during other parts of their life cycle or how patterns vary among years. Continued studies of C. glacialis distribution, morphometrics, and gene expression could address these questions and serve as a harbinger for responses to future climatic changes.

中文翻译：

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白令海东部冰川Calanus 脂相关基因表达和饥饿敏感性

摘要：在白令海东部，Calanus属富含脂质的桡足类动物有助于维持高产渔业和通过生态系统的高效能源流动。在夏季和秋季，Calanus种群主要由 C5 期桡足类组成，它们储存脂质并准备休眠（滞育）。我们于 2015 年初秋从东部白令海架收集了Calanus C5 桡足类，并检查了Calanus物种组成、形态特征和脂质相关基因表达是否沿南北梯度变化。采样区域在温度、叶绿素a和Calanus丰度方面表现出显着差异。然而，卡兰纳斯种群出人意料地同质，几乎完全由C. glacialis 组成，没有证据表明在 prosome 大小、油囊丰满度或脂质相关基因表达方面存在纬度趋势。我们发现来自普里比洛夫群岛附近 1 个南部站的C. glacialis更大，并且表现出较低的油囊丰满度和较高的脂质储存基因表达，而不是纬度梯度。相对于与船上喂养实验相关的大转变，跨站的基因表达变化很小。C. glacialis跨站的相似特征意味着大多数 C5 桡足类动物经历了有利的生长条件，无论其纬度位置如何。目前尚不清楚环境条件如何影响C. glacialis在其生命周期的其他部分的生理学或模式如何随年份变化。对C. glacialis分布、形态测量学和基因表达的持续研究可以解决这些问题，并作为对未来气候变化做出反应的先兆。