Collaborative research: The effects of predator traits on the structure of oceanic food webs

食物网描述谁吃谁，追踪从植物到大型动物的能量流动。虽然陆地上食物网中的许多联系是相当熟悉的，但我们对海洋食物网的理解存在很大差距。缩小这些差距对于了解营养物质和能量如何在海洋生态系统中流动、生物如何在海洋中相互作用以及如何最好地管理海洋资源至关重要。这个项目将研究海洋食物网络结构，重点是管水母类，这是一种在开阔海洋中丰富的捕食者群体，形成的群体长度从不到一英寸到超过一百英尺不等。管水母类被认为是海洋食物网中的重要捕食者，但它们很难研究，因为它们生活在巨大的海洋深处，而且胶状而脆弱。关于它们吃什么的细节，以及它们生物学的许多其他特征，人们仍然知之甚少。这个项目将结合对摄食的直接观察、管水母肠道内容物的遗传分析和稳定同位素分析来识别不同种类的管水母细胞吃什么。这将对食物网的结构如何产生提供新的理解，有助于我们预测随着全球气候变化未来食物网的变化。管水母类以一种独特的方式进食--它们有专门用于捕获猎物的高度专业化的触角--因此，捕获的猎物在很大程度上取决于这些触角的解剖和功能。该项目将描述这些触角，重建它们的进化史，并调查触角结构的进化变化如何导致饮食变化。该项目将培养一名博士生、一名硕士生、一名博士后和本科生，包括代表人数不足的群体的个人。该项目将支持制作科学严谨而又引人入胜的视频，促进公民科学计划的扩展，并创建K-12教学模块。该项目将推进三个科学目标：首先，它将使用肠道内容物和猎物区域的DNA元编码、猎物相遇的遥控飞行器(ROV)视频和稳定同位素分析来识别各种管水母的食物。这些方法具有很强的互补性，可以进行广泛的交叉验证。其次，该项目将通过将管水母类食物与每一物种栖息地的相对猎物丰度进行比较，来表征管水母类食物的选择性。第三，该项目将通过对管水母类猎物的触角和线囊进行详细的形态分析，确定不同物种的管水母类猎物捕获装置的结构特征。这些数据将被整合到一个生态和进化框架中，以确定与猎物专门化相关的捕食者特征。在更大的背景下，解决这些问题将通过揭示捕食者选择性的进化变化如何与栖息地和摄食装置的进化变化相对应，以及这些变化如何塑造公海当前的食物网络结构，来促进我们对海洋捕食行为的理解。该团队将测试和改进描述食物网络拓扑结构和起源的综合方法，并评估系统发育关系解释猎物选择性的可能性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Food webs describe who eats whom, tracing the flow of energy from plants up to large animals. While many connections in food webs on land are quite familiar, there are large gaps in our understanding of ocean food webs. Closing these gaps is critical to understanding how nutrients and energy move through ocean ecosystems, how organisms interact in the ocean, and how best to manage ocean resources. This project will study ocean food web structure with a focus on siphonophores, an abundant group of predators in the open ocean that form colonies that range in length from less than an inch to more than one hundred feet. Siphonophores are known to be important predators within ocean food webs, but they are difficult to study because they live across great ocean depths and are gelatinous and fragile. The details of what they eat, as well as many other features of their biology, remain poorly known. This project will combine direct observations of feeding, genetic analysis of siphonophore gut contents, and stable isotope analyses to identify what different species of siphonophores eat. This will provide a new understanding of how the structure of food webs arise, aiding in our ability to predict future changes to food webs as the global climate shifts. Siphonophores feed in a unique manner--they have highly specialized tentacles that are used solely for capturing prey--thus, the prey captured is determined largely by the anatomy and function of these tentacles. The project will describe these tentacles, reconstruct their evolutionary history, and investigate how evolutionary shifts in tentacle structure have led to changes in diet. This project will train one PhD student, one Master's student, a postdoc, and undergraduate students, including individuals of underrepresented groups. This project will support the production of scientifically rigorous yet engaging videos, foster the expansion of a citizen-science program, and create K-12 teaching modules.This project will advance three scientific aims: First, it will identify the diet of a diverse range of siphonophores using DNA metabarcoding of gut contents and prey field, remotely operated vehicle (ROV) video of prey encounters, and stable isotope analysis. These approaches are highly complementary and allow for extensive cross validation. Second, the project will characterize the selectivity of siphonophore diets by comparing them to the relative prey abundances in the habitats of each of these species. Third, the project will characterize the structure of the siphonophore prey capture apparatus across species through detailed morphological analysis of their tentacles and nematocysts. These data will be integrated in an ecological and evolutionary framework to identify predator features associated with prey specialization. In a larger context, addressing these questions will advance our understanding of oceanic predation by revealing how evolutionary changes in predator selectivity correspond to evolutionary changes in habitat and feeding apparatus and how these changes shape current food web structure in the open ocean. The team will test and refine an integrated approach to describing the structure and origin of food web topology, and evaluate the potential for phylogenetic relationships to explain prey selectivity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.