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

食物网描述了谁吃谁，追踪从植物到大型动物的能量流动。虽然陆地食物网中的许多联系都很熟悉，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的结构，重点是虹吸管，这是一种在开放海洋中丰富的捕食者群体，它们形成的群落长度从不到一英寸到一百多英尺不等。众所周知，管水母是海洋食物网中重要的捕食者，但它们很难研究，因为它们生活在海洋深处，呈胶质状，很脆弱。关于它们吃什么的细节，以及它们的许多其他生物学特征，人们仍然知之甚少。该项目将结合直接的摄食观察、虹吸水母肠道内容物的遗传分析和稳定同位素分析来确定不同种类的虹吸水母吃什么。这将对食物网的结构是如何产生的有一个新的认识，帮助我们预测未来随着全球气候变化食物网的变化。管水母以一种独特的方式进食——它们有高度专业化的触角，专门用来捕捉猎物——因此，捕获的猎物在很大程度上取决于这些触角的解剖结构和功能。该项目将描述这些触须，重建它们的进化历史，并研究触须结构的进化变化如何导致饮食的变化。该项目将培养1名博士生、1名硕士生、1名博士后和1名本科生，包括代表性不足群体的个人。该项目将支持制作科学严谨但引人入胜的视频，促进公民科学项目的扩展，并创建K-12教学模块。该项目将推进三个科学目标：首先，它将利用肠道内容物和猎物场的DNA元条形码、猎物遭遇的远程操作车辆（ROV）视频和稳定同位素分析来确定各种虹吸管的饮食。这些方法是高度互补的，并允许广泛的交叉验证。其次，该项目将通过将虹吸虫饮食与这些物种栖息地中相对猎物丰度进行比较，来表征虹吸虫饮食的选择性。第三，该项目将通过对虹吸水母的触须和刺丝囊的详细形态学分析来表征其跨物种猎物捕获装置的结构。这些数据将被整合到生态和进化框架中，以确定与猎物专业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的进化变化如何对应栖息地和喂养装置的进化变化，以及这些变化如何塑造开阔海洋中当前的食物网结构，促进我们对海洋捕食的理解。该团队将测试和完善一种描述食物网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潜力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.