Collaborative Research: MUCUS: Measuring and Understanding the Cassiopea Use of Space

近几十年来，超过50%的活珊瑚礁已经消失，很大程度上是由于气候变化和其他人为因素。相比之下，自1950年以来，水母正在部分海洋中过度繁殖，水母的繁殖速度加快。水母产生的粘液可能会让它们在新的地方定居，在温暖的环境中茁壮成长，并为周围的群落提供糖蛋白。虽然已经有大量的工作探索粘液在脊椎动物中的作用，以及粘液如何在微尺度上影响微生物游泳，但我们对水母粘液的机械特性的了解有限，水母的粘液厚度可能高达数十厘米。这个项目的主要目标是确定仙后座水母及其近缘物种的成功是否部分归因于它们大量产生粘液，以及与之相关的水母在被称为仙后体的结构中释放的刺细胞内的毒液。该项目支持一名博士后、两名研究生和至少四名本科生在生物力学、数学建模、生理学和生态学方面的跨学科培训。培训包括为学生提供与史密森学会、重要的拉戈海洋研究实验室以及日本和巴西的国际研究人员建立联系的机会。虽然科学研究和新闻报道越来越多地报道一些海洋物种的分布范围缩小，但反过来，由于水华事件增加，水母类水母的分布范围似乎正在扩大。温度似乎是导致更长繁殖期的主要因素，导致无性生殖增加的人为因素也是如此。越来越多的研究结果还表明，水母的粘液可能会发挥保护作用，抵御环境压力和升高温度，同时提高摄食效率，从而带来优势。为了了解粘液如何帮助仙后座和其他根茎水母成功繁殖，研究小组将使用一种高度跨学科的方法，结合下列工具：(1)数学和工程工具，以表征粘液的物理性质以及浮游生物和丝虫在其中的运动性；(2)EDNA，传统采样，和基准基准仙后座物种分布如何变化的文献；(3)纳米孔Erna测序，以表征毒液及其他相关粘液蛋白质的特征，以及这些蛋白质的表达如何随着时间和季节性温度的波动而变化。然后，该团队将应用这些工具来(1)评估粘液是否以及如何在允许或可能增强仙后座的主动移动的同时降低各种浮游猎物的游泳速度；(2)确定粘液保护水母免受异物和刺激物伤害的机制；以及(3)评估粘液、仙客体和线虫是否以及如何通过创建优势的单特异性或单属群落来帮助仙后座的范围扩大。除了为博士后、研究生和本科生提供跨学科培训机会外，该奖项还支持在重点拉戈海洋研究实验室举办的仙后座生物学年度研讨会，该研讨会将扩大到包括与该研究项目相关的演讲和教程。该奖项由生物IOS-生理机制和生物力学计划以及GEO-OCE-生物海洋学计划共同资助。该奖项反映了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。

In recent decades over 50% of living coral reefs have been lost due in large part to climate change and other anthropogenic factors. In contrast, jellyfish are overpopulating part of the oceans with an increased rate of blooms since 1950. Mucus produced by jellyfish may allow them to colonize new locations, thrive in warm environments, and provide glycoproteins for the surrounding community. Although there has been significant work exploring the role that mucus plays in vertebrate animals and how mucus affects microorganism swimming at the microscale, our understanding of the mechanical properties of jellyfish mucus, which may be up to tens of centimeters in thickness, is limited. The broad goal of this project is to determine if the success of the jellyfish Cassiopea and related species is due in part to their significant production of mucus and, associated with it, venom within stinging cells released by the jellyfish in structures called cassiosomes. This project supports interdisciplinary training for a postdoctoral fellow, two graduate students, and at least four undergraduates at the interface of biomechanics, mathematical modeling, physiology, and ecology. Training includes opportunities for students to connect with researchers at the Smithsonian Institution, the Key Largo Marine Research Laboratory, and internationally in Japan and Brazil. While scientific studies and news stories increasingly report on the reduction of distribution ranges for a number of marine species, scyphozoan jellyfish, conversely, appear to be undergoing range expansions due to increased bloom events. Temperature appears to be a major factor, enabling a longer reproduction period, as are anthropogenic factors that result in an increase in asexual reproduction. Increasing findings also suggest that jellyfish mucus may confer an advantage by playing a protective role against environmental stress and increasing temperatures while simultaneously enhancing feeding efficiency. To understand how mucus aids in the success of Cassiopea and other rhizostome jellyfish, the research team will use a highly interdisciplinary approach that combines the following tools: (1) mathematics and engineering tools to characterize the physical properties of the mucus and the motility of plankton and cassiosomes within it, (2) eDNA, traditional sampling, and the literature to benchmark how Cassiopea species distributions are changing, and (3) Nanopore eRNA sequencing to characterize the venom and other mucus proteins of interest and how expression of these proteins changes over time and with seasonal temperature fluctuations. The team will then apply these tools to (1) assess whether and how mucus reduces swimming speeds in a variety of planktonic prey while permitting or possibly enhancing active locomotion in cassiosomes, (2) determine the mechanisms by which mucus protects jellyfish from foreign objects and irritants, and (3) evaluate if and how mucus, cassiosomes, and nematocysts aid in the range expansion of Cassiopea by creating dominant mono-specific or mono-generic communities. In addition to providing interdisciplinary training opportunities for a postdoctoral fellow and graduate and undergraduate students, the award supports an annual workshop on Cassiopea biology at the Key Largo Marine Research Laboratory which will be expanded to incorporate presentations and tutorials related to this research project.This award is co-funded by the BIO-IOS-Physiological Mechanisms and Biomechanics program and the GEO-OCE-Biological Oceanography program.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.