Feeding and food limitation in copepod nauplii, the neglected life stage

桡足类无节幼体的摄食和食物限制，被忽视的生命阶段

• 批准号: 0929075
• 负责人: William Kimmerer
• 金额: $ 52.4万
• 依托单位: San Francisco State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0929075&HistoricalAwards=false
• 关键词: Feeding; food; limitation; copepod; nauplii

This project will investigate feeding by copepod nauplius larvae, the most abundant metazoans in the sea. It will answer three questions: 1) How does food selection by adults and nauplii differ when they are fed multiple prey species in the laboratory? 2) How does food selection by adults and nauplii differ when they are feeding on natural prey assemblages? and, 3) How do growth, development, and survival differ between copepodites and nauplii when their growth is food limited? Comparative experiments and field-based measurements will contrast the food consumed, and the effects of food limitation, between nauplii and later life stages. This contrast will include attributes of food such as size, taxon, and motility, and will include experiments with cultured prey offered singly or in a mixture, and natural prey, and apply genetic techniques to determine prey consumption by a predatory copepod. Copepods will be collected from the San Francisco Estuary, with four species selected for experiments to span taxonomic groups, sizes, salinity ranges, and general feeding behavior. A variety of techniques will be applied to account for the inevitable biases and limitations of each; all but one have previously been applied in our laboratories. These will include laboratory feeding experiments using cultured prey individually and in mixtures, and experiments using natural prey. Consumption of prey in experimental bottles will be measured as chlorophyll concentration and through particle counts by microscopy and flow cytometry. Radioactively labeled prey will be used in short incubations to determine feeding on particular prey types. Samples from the field will be examined for gut fluorescence. Separate experiments will determine how nauplii and copepodites survive and grow at different concentrations of food. Investigations of feeding by a predatory copepod (Tortanus dextrilobatus) will use molecular techniques to identify mitochondrial and nuclear DNA from diverse suspected prey species. Specific primers will be developed for common zooplankton species consumed by T. dextrilobatus in the laboratory. General primers and screening protocols developed here will be useful for identifying food web interactions in other estuarine communities.Copepod nauplii are important both in their diverse trophic roles in ocean foodwebs and in the population dynamics of copepods. Nauplii have a completely different feeding apparatus from later stages, and the first feeding stage can be very sensitive to starvation, making these life stages critical to population dynamics. Yet extant copepod population models treat nauplii as miniature adults. This work will provide valuable input to the growing efforts at modeling ocean ecosystems. This project will also support two Master's theses at San Francisco State University, a minority-serving institution. The project will provide continuing opportunities for training undergraduates, including URM students, in genetics and field ecology at the Romberg Tiburon Center for Environmental studies, an NSF FSML-supported field station on San Francisco Bay.

本项目将研究海洋中数量最多的后生动物——鹦鹉螺桡足类幼体的摄食。它将回答三个问题：1)在实验室中，当成年和鹦鹉螺被喂食多种猎物时，它们的食物选择有何不同？2)当成虫和鹦鹉螺捕食自然猎物时，它们的食物选择有何不同？3)当桡足动物和鹦鹉螺的生长受到食物限制时，它们的生长、发育和生存有何不同？比较性实验和实地测量将对比幼年和后期阶段所消耗的食物，以及食物限制的影响。这种对比将包括食物的属性，如大小、分类群和运动性，并将包括单独或混合提供的人工猎物和天然猎物的实验，并应用遗传技术来确定掠食性桡足动物的猎物消耗。将从旧金山河口收集桡足类，选择四种进行实验，以跨越分类群，大小，盐度范围和一般摄食行为。将应用各种技术来解释每种方法不可避免的偏差和局限性；除一种外，其他都曾在我们的实验室中应用过。这些实验将包括单独和混合使用人工养殖猎物的实验室喂养实验，以及使用天然猎物的实验。实验瓶中猎物的消耗量将通过叶绿素浓度和显微镜和流式细胞术的颗粒计数来测量。放射性标记的猎物将在短暂的孵化中用于确定对特定猎物类型的摄食。将对现场采集的样本进行肠道荧光检测。单独的实验将确定nauplii和桡足动物如何在不同浓度的食物中生存和生长。研究掠食性桡足动物（Tortanus dextrilobatus）的食性将使用分子技术来识别各种可疑猎物物种的线粒体和核DNA。在实验室中，针对常见的浮游动物种类，将开发特定的引物。本文开发的一般引物和筛选方案将有助于识别其他河口群落的食物网相互作用。桡足类在海洋食物网中具有丰富的营养作用，在桡足类种群动态中具有重要意义。鹦鹉螺的摄食器官与后期完全不同，第一个摄食阶段对饥饿非常敏感，使这些生命阶段对种群动态至关重要。然而，现存的桡足动物种群模型将nauplii视为微型成年动物。这项工作将为不断增长的海洋生态系统建模工作提供宝贵的投入。该项目还将支持旧金山州立大学的两篇硕士论文，这是一所为少数族裔服务的机构。该项目将在Romberg Tiburon环境研究中心为本科生（包括URM学生）提供遗传学和野外生态学方面的持续培训机会。该中心是一个由NSF fsml支持的位于旧金山湾的野外研究站。