Lipid Transformations of Euchaeta antarctica, a Carnivorous Marine Copepod

这项研究将研究南极掠食性桡足类动物南极洲欧查埃塔的生态学，它是南极半岛外的一个深盆地克罗克海峡的一种重要的大型浮游食肉动物，以生物量为主。先前的研究表明，以甲壳类猎物为食的大小选择足以弥补呼吸成本，因此这种富含脂肪的大型桡足类动物可以储存多余的食物。随着冬季的到来，摄食停止，呼吸和排泄率下降，氧/氮比上升，表明从以蛋白质和脂肪为基础的代谢转变为以脂肪为主导的代谢，证实了夏季的摄食活动和冬季对脂质的依赖。在冬天，几乎所有的雌性都是生殖成熟的，从它们的母体储藏室中产生多窝富含脂肪的卵。早期阶段成熟缓慢，因此第一个摄食阶段出现在浮游生物身上，与南部水域的活跃水华同步。在这一极地地区，食物供应的极端季节性要求将两个过程分开：夏季取食和冬季繁殖。这个项目将完成脂类分析，这是这项研究的一个重要组成部分。以前采集的样本可以分析三个不同季节的不同桡足类阶段的总脂含量、脂类组成和生产率，以及冬季成年雌性的不同生殖状态。这项工作将能够评估储存的储备是否足以提供能量来支持冬季代谢率和生殖需求，并将使人们了解脂质含量/组成与生活史战略之间的联系。

This research will address the ecology of an Antarctic predatory copepod, Euchaeta antarctica, a biomass dominant and important macroplanktonic carnivore in Croker Passage, a deep basin off the Antarctic peninsula. Previous work has shown that size-selective feeding on crustacean prey more than adequately covers respiratory costs so excess dietary input could be stored by this large lipid-rich copepod. With the onset of winter, feeding stops, respiration and excretion rates decline and oxygen/nitrogen ratio increases, indicating a shift from a protein and lipid based metabolism to a lipid-dominated metabolism, corroborating summer feeding activity and winter reliance on lipids. During winter, nearly all females are reproductively mature, producing multiple clutches of lipid-rich eggs from their maternal stores. Early stages mature slowly so the first feeding stage appears in the plankton in synchrony with the active bloom in southern waters. The extreme seasonality of food availability in this polar region enforces the separation of 2 processes: feeding in summer and reproduction in winter. This project will complete the lipid analyses, an essential component of this research. Samples, previously collected, permit an analysis of total lipid content, lipid class composition and production rates by different copepodid stages during three different seasons, and by different reproductive states of the adult female in the winter. This work will allow for an evaluation of whether the stored reserves are sufficient to provide energy to support winter metabolic rates and reproductive demands and will provide an understanding of the linkage between lipid content/composition and life history strategies.