Collaborative Research: The effects of diatom-produced polyunsaturated aldehydes on the microbial food wed in temperate and polar waters

概述：本项目将进行一系列现场/实验室实验，以解决以下关于微型浮游动物（消费者在20-200微米之间）和硅藻产生的多不饱和醛的假设：1 .醛会损害微型浮游动物对硅藻和非硅藻浮游植物的食草性。2。醛类会降低微型浮游动物和不产生聚丙烯酸的浮游植物的生长速度。3。在产生醛的硅藻存在的情况下，桡足类会转向小型浮游动物，而无毒（轻度）的硅藻将成为桡足类的重要食物来源。醛类对微型浮游动物和桡足类动物的影响将取决于捕食者先前暴露于多酚a的程度。实验将包括天然浮游生物、捕获的桡足类动物、培养的马里诺骨骼肌（SM）（包括其产醛菌株）和合成醛。为了深入了解浮游生物群落中复杂的相互作用，将使用显微镜、流式细胞术和细胞学方法获得浮游生物群落的组成、丰度和动态的详细信息。这种方法将允许pi得出关于硅藻产生的醛在浮游植物-微型浮游动物-桡足动物营养相互作用中的作用的结论。pi将与安东·多恩动物园（那不勒斯，意大利）的PUA研究小组协调工作并交换信息。智力优势：硅藻是海洋中主要的自养浮游生物。最近的证据表明，微型浮游动物是主要的食草动物，而桡足类通常依赖于微型浮游动物作为食物，除了在硅藻生产高峰期。小型浮游动物以大型硅藻为食，并且生长速度与它们的藻类猎物一样快，这就引出了一个问题：是什么让硅藻在藻华的初始阶段逃脱了小型浮游动物的放牧控制，并保持藻华直到营养资源耗尽？化感作用在浮游植物中广泛存在。在浮游生物化感作用的研究中，世界性的形成花的SM产生多种醛，并已成为一种模式生物。大多数关于硅藻细胞毒性的研究都致力于抑制海洋无脊椎动物的繁殖和发育，而令人惊讶的是，关于其对硅藻主要食草动物微型浮游动物的影响的研究很少。切萨皮克湾的初步结果表明，醛类物质可能在浮游生物群落中引起级联效应。该研究将：(1)提高我们对沿海海洋中硅藻-微型浮游动物-桡足动物关键联系的认识；(2)生成化感作用对海洋食物网影响的新数据；(3)通过比较温带大西洋水域浮游生物的结构和动态，有助于我们对海洋生态系统更广泛的模式的理解；(4)通过国际合作推进生物海洋学。更广泛的影响：阿克伦大学和马里兰大学的一名博士后、两名研究生和几名本科生将作为该项目的结果接受培训。这个项目将吸引有进取心的少数民族学生加入这个项目。该研究将通过与WVIZ Ideastream网络合作的交互式远程学习系列，扩展到7-12年级的学生和教师。ppi将继续与大湖科学中心（Great Lakes Science Center）现有的外展合作伙伴关系，该中心最近举办了一场关于北极变化和nsf赞助的研究的电子演示，吸引了大约4.5万名参观者。pi还将与克利夫兰自然历史博物馆合作开发公共项目，并与国家发明家名人堂STEM中学合作开发以极地研究为重点的课程。课程模块将在一个专门的网站上免费下载。更广泛的影响有限责任公司将评估这些教育和推广活动。

Overview: This project will conduct a set of field/laboratory experiments to address the following hypotheses with respect to microzooplankton (consumers between 20-200 µm) and diatom- produced polyunsaturated aldehydes: I. Aldehydes will impair microzooplankton herbivory on diatoms and non-diatom phytoplankton. II. Aldehydes will reduce the growth rates of microzooplankton and non PUA-producing phytoplankton. III. In the presence of aldehyde-producing diatoms, copepods will switch to microzooplankton, whereas non- (mildly)- toxic diatoms will be an important food source for copepods. IV. The effects of aldehydes on microzooplankton and copepods will depend on the grazers' prior exposure to PUA. The experiments will include natural plankton, captured copepods, cultured Skeletonema marinoi (SM), including its aldehyde-producing strain, and synthetic aldehydes. To gain insights into complex interactions within planktonic communities, detailed information on their composition, abundance, and dynamics will be obtained using microscopy, flow-cytometry, and cytological methods. This approach will allow the PIs to draw conclusions about the role of diatom-produced aldehydes in phytoplankton-microzooplankton- copepod trophic interactions. The PIs will coordinate efforts and exchange information with the PUA study group at the Stazione Zoologica Anton Dohrn (Naples, Italy).Intellectual merit: Diatoms are dominant autotrophic plankton in the ocean. Recent evidence indicates that microzooplankton are the dominant herbivores, whereas copepods often rely on microzooplankton as food, except during peak diatom production. The ability of microzooplankton to feed on large diatoms and grow as fast as their algal prey leads to the question of what allows diatoms to escape microzooplankton grazing control during the initial phases of their blooms and maintain the blooms until nutrient resources are depleted? Allelopathy is wide spread among phytoplankton. The cosmopolitan bloom-forming SM produces several aldehydes and has become a model organism in plankton allelopathy studies. Most studies on diatom cytotoxicity have been dedicated to inhibitory effects on reproduction and development of marine invertebrates, whereas surprisingly little information exists on its impact on key diatom grazers, microzooplankton. Preliminary results in the Chesapeake Bay show that aldehydes may induce cascading effects within planktonic communities. The proposed study will: (1) Improve our knowledge of the critical diatom-microzooplankton-copepod links in the coastal ocean; (2) Generate novel data on the effects of allelopathy on marine food webs; (3) Contribute to our understanding of broader patterns of marine ecosystems by comparing plankton structure and dynamics in the temperate Atlantic waters; (4) Advance biological oceanography through international collaboration.Broader Impacts: One post-doctoral fellow, two graduate students and several undergraduate students at the Universities of Akron and Maryland will be trained as a result of this project. The project will attract motivated minority students into the program. The research will be extended to students in grades 7-12 and teachers via an interactive distance learning series in collaboration with the WVIZ Ideastream network. The PIs will continue an existing outreach partnership with the Great Lakes Science Center, where a recent electronic presentation dedicated to Arctic change and NSF-sponsored research was seen by ca. 45,000 visitors. The PIs will also work with the Cleveland Museum of Natural History to develop public programs, and with the National Inventors Hall of Fame STEM Middle School to develop a curriculum focused on polar research. Curriculum modules will be available as free downloads from a dedicated website. Broader Impacts, LLC, will evaluate these education and outreach activities.