Fecal Pellets of Doliolids and Copepods: Two Different Microworlds?

多利奥利德和桡足类的粪便颗粒：两个不同的微观世界？

• 批准号: 1031263
• 负责人: Gustav-Adolf Paffenhofer
• 金额: $ 58.52万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1031263&HistoricalAwards=false
• 关键词: Fecal; Pellets; Doliolids; Copepods; Two

High primary productivity on wide subtropical continental shelves has been related to upwellings generated by western boundary currents. Studies on the U.S. southeastern (SE) shelf have revealed frequent occurrences of patches of pelagic tunicates which can rapidly colonize the SE shelf and consume a large percentage of the primary productivity. Since these tunicates are, as compared to copepods, rather inefficient in utilizing the ingested phytoplankton, large amounts of the ingested organic matter should be available to other consumers which might represent different microworlds. While among the neritic metazoa calanoid copepods have been considered the main consumers of larger phytoplankton cells, among protists heterotrophic dinoflagellates can feed on such cells. Neritic salps and doliolids, because of their occasional occurrence, were only seen as occasional major consumers. Doliolids are now known to occur predictably on the SE shelf through much of the year, and because of their inefficient use of phytoplankton, their effects on the shelf food web might be considerable. This project will investigate processes related to the early decomposition of doliolid fecal pellets and compare these processes to pellet decomposition of co-occurring calanoid copepods. The investigators will test several hypotheses related to the main question: How do the early decomposition rates of fecal pellets of doliolids and copepods compare, and how are they related to the abundance, size and processes of heterotrophic prokaryotes? As the feeding processes differ between calanoid copepods and doliolids, major differences in early decomposition are expected. This should influence the pelagic microbial loop of productive subtropical shelves.The research focuses on a central theme, processing of biogenic material, within the diverse field of marine plankton, marine biogeochemistry, and shelf oceanography, and therefore will be of interest well beyond the specific focus of the project. Because thaliacean abundance is a common feature of western boundary continental shelf environments, the findings of this study will be applicable well beyond the South Atlantic Bight. Moreover, the project will target three important education and broader impact themes: 1) Teacher education; 2) Demographic diversification of future ocean scientists;and 3) Strengthening international science collaboration. To help bridge the gap between research and K-12 students and teacher communities, a collaboration with an ongoing science teacher program sponsored by The Georgia Aquarium and NOAA (Rivers to Reef Educator Workshop) the investigators will interact with 96 K-12 in-service science teachers and provide them with oceanographic research experience and novel insights into the specific questions currently being addressed in plankton ecology. By supporting undergraduate students (largely African American) through a well established relationship with Savannah State University, the project will contribute to the effort to increase the diversity of future ocean scientists and professionals. Finally, a strong component of collaboration with colleagues in Germany and Norway will further the scientific objectives of the project and strengthen collaborations between US and European biological oceanographers.

广阔的副热带大陆架上的高初级生产力与西部边界流产生的上升流有关。对美国东南部陆架的研究表明，中上层被囊动物斑块频繁出现，它们能够迅速在东南陆架定居并消耗大量初级生产力。由于与桡足类动物相比，这些被囊动物在利用摄入的浮游植物方面效率相当低，因此大量摄入的有机物质应该可供其他消费者使用，这些消费者可能代表不同的微观世界。虽然浅海后生动物桡足类被认为是较大浮游植物细胞的主要消费者，但在原生生物中，异养甲藻可以以此类细胞为食。浅海樽海鞘和海藻类由于偶尔出现，仅被视为偶尔的主要消费者。现在已知，一年中的大部分时间，多利奥利德都会在东南大陆架上出现，并且由于它们对浮游植物的利用效率低下，它们对大陆架食物网的影响可能相当大。该项目将研究与多利奥利德粪便颗粒早期分解相关的过程，并将这些过程与同时存在的桡足类粪便颗粒分解进行比较。研究人员将测试与主要问题相关的几个假设：多利奥利德和桡足类粪便颗粒的早期分解率如何比较，以及它们与异养原核生物的丰度、大小和过程有何关系？由于桡足类和长足类的摄食过程不同，因此预计早期分解存在重大差异。这应该会影响生产性副热带陆架的中上层微生物循环。该研究的重点是海洋浮游生物、海洋生物地球化学和陆架海洋学等不同领域内的生物材料加工这一中心主题，因此其兴趣将远远超出该项目的具体重点。由于海藻丰富度是西部边界大陆架环境的一个共同特征，因此这项研究的结果将适用于南大西洋湾以外的地区。此外，该项目将针对三个重要的教育和更广泛影响的主题：1）教师教育； 2) 未来海洋科学家的人口结构多样化；3) 加强国际科学合作。为了帮助弥合研究与 K-12 学生和教师社区之间的差距，与乔治亚水族馆和 NOAA（河流到珊瑚礁教育者研讨会）赞助的正在进行的科学教师计划合作，研究人员将与 96 名 K-12 在职科学教师互动，为他们提供海洋学研究经验和对当前浮游生物生态学中正在解决的具体问题的新颖见解。通过与萨凡纳州立大学建立的良好关系，为本科生（主要是非裔美国人）提供支持，该项目将有助于增加未来海洋科学家和专业人员的多样性。最后，与德国和挪威同事的合作将进一步推进该项目的科学目标，并加强美国和欧洲生物海洋学家之间的合作。