Doliolid Blooms: What Are the Driving Variables? Investigations of Trophic Interactions

众所周知，亚热带海洋的浅海区域经历了中上层被衣藻水华的时断时续。然而，关于调节这些种群的过程或它们的生态意义，人们知之甚少。根据零星的野外观察和相对较少的实验室研究，可以理解的是，从理论上讲，水母的开花可能特别重要，因为它们具有巨大而快速的无性繁殖能力。据报道，世界上大多数大陆架上都有超过1,000个m-3动物园的水华。大量的水华有可能通过消耗卵限制桡足类的生产，并通过粪便生产将初级生产分流到底栖生物和微生物圈，从而重组大陆架远洋生态系统的营养结构。尽管通过仔细的实验室研究已经学到了很多东西，但在实验室中还不能令人满意地模拟控制浮游动物水华发展的过程，而且直到最近，还缺乏在现场调查浮游动物及其猎物和捕食者之间营养相互作用的关键方面的方法。在这个项目中，研究人员将进行一项基于现场的研究，将经典的和经过验证的浮游动物生态学方法与新的基于分子的方法相结合，以评估肠道内容物，以解决关于南大西洋海湾大陆架夏季水华期间浮游动物营养相互作用的几个基本问题。该项目的两个方面可能被认为具有潜在的变革性。首先，它将是第一个系统地在现场应用浮游动物分子肠道含量分析方法的公司之一，可能会给浮游动物生态学领域带来革命性的变化。值得注意的是，科学界已明确指出，需要新的工具来研究浮游动物的营养过程是该领域的一个主要限制。其次，该项目将探索一种范式转换假说，即浮游植物水华不是由直接捕食、营养限制或平流海洋过程控制，而是由不断变化的食物颗粒环境控制。研究集中在海洋浮游生物研究的不同领域中的一个中心主题-营养相互作用，因此将远远超出该项目的特定重点。在更广泛的程度上，这项研究将有助于弥合分子、有机体和生态学之间存在的现代生物学的根本分歧。该项目的一个重要组成部分将涉及培训和增加在STEM领域任职人数不足的学生。1名研究生和3名本科生将得到支持和培训。通过与两所历史悠久的黑人大学建立良好的关系，调查人员将积极招生，这两所大学都有海洋科学课程(汉普顿大学和萨凡纳州立大学)。此外，其中一名研究人员是汉普顿大学的一名年轻助理教授，该项目将为她提供机会推进她的研究生涯，改善汉普顿的研究基础设施，并增加学生接触研究的机会。最后，该项目将利用与北欧研究人员建立的国际关系，这些研究人员积极从事类似的研究，但重点是附肢动物和其他胶状远洋物种。该项目还将支持美国海洋科学家参加即将于2009年在萨凡纳组织的分子营养相互作用II专题讨论会。

It is well known that neritic regions of subtropical oceans experience episodic occurrences of pelagic tunicate blooms. However, little is known regarding the processes that regulate these populations or their ecological significance. Based on sporadic field observations and a relatively small number of laboratory studies, it is understood that theoretically blooms of the Thaliacea, specifically the doliolids, may be particularly important because of their enormous and rapid asexual reproductive capacity. Blooms of over 1,000 zooids m-3 are reported from most of the world's continental shelves. Large blooms of doliolids have the potential of restructuring the trophic structure of shelf pelagic ecosystems by limiting copepod production via consumption of eggs and shunting primary production to the benthos and the microbial loop via fecal production. Although much has been learned via careful laboratory studies, investigation of the processes that govern the development of doliolid blooms cannot be satisfactorily simulated in the laboratory and, until recently, methods to investigate key aspects of trophic interactions between zooplankton, their prey, and their predators in situ have been lacking. In this project the investigators will conduct a field-based study in which classical and proven zooplankton ecology methods will be merged with new molecular based approaches for assessing gut contents to address several fundamental questions concerning doliolid trophic interactions during summer blooms on the South Atlantic Bight continental shelf.Two aspects of the project may be considered potentially transformative. First, it will be among the first to systematically apply zooplankton molecular gut content analytical methods in situ, potentially revolutionizing the field of zooplankton ecology. It is of note that the need for new tools to investigate zooplankton trophic processes has been clearly identified by the science community as a major limitation to the field. Second, the project will explore a paradigm shifting hypothesis that doliolid blooms are controlled not by direct predation, nutrient limitation, or advective oceanographic processes, but by a changing food particle environment.The research focuses on a central theme, trophic interactions, within the diverse field of marine plankton studies, and therefore will be of interest well beyond the specific focus of the project. To a broader degree, the study will serve to help bridge the fundamental divide in modern biology that exists between molecules, organisms, and ecology. An important component of the project will involve training and increasing representation of underrepresented students in STEM fields. One graduate student and three undergraduate students will be supported and trained. Through well established relationships with two Historically Black Universities, both of which have Marine Science programs (Hampton University and Savannah State University), the investigators will aggressively recruit students. Additionally, one of the investigators is a young assistant professor at Hampton University and this project will provide her opportunities to advance her research career, improve research infrastructure at Hampton, and increase student exposure to research. Finally, this project will take advantage of established International relationships with Nordic researchers who are actively engaged in similar research but focused on Appendicularians and other gelatinous pelagic species. The project will also support the participation of US marine scientists in the upcoming Molecular Trophic Interactions II symposium being organized in Savannah in 2009.