Evolution of Morphology and Trophic Strategies in Antarctic Agglutinated Foraminifera

南极凝集有孔虫的形态演化和营养策略

• 批准号: 0440769
• 负责人: Samuel Bowser
• 金额: --
• 依托单位: Health Research Incorporated/New York State Department of Health
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0440769&HistoricalAwards=false
• 关键词: Evolution; Morphology; Trophic; Strategies; Antarctic

Foraminifera ("forams") are structurally complex, abundant, and widely distributed protists. Allogromiid forams often dominate deep-sea and high-latitude assemblages, and are believed to aggressively rework sediments in these habitats. Allogromiids are also common in continental slope systems, which are important for the recycling of organic matter and hence for global biogeochemical cycles. Most studies of foram biology have focused on species from shallow tropical/temperate settings, where they have been shown to employ diverse trophic strategies ranging from osmotrophy to metazoan carnivory. As a major meio- and macrofaunal component in deeper settings, a better understanding of the in situ behavior and feeding biology of basal allogromiids is of major importance to the ocean sciences. Explorers Cove, Antarctica, is currently the only place on Earth where biologists can use scuba to directly access a "deep-sea-like" ecosystem and collect basal allogromiids in bulk; it is therefore a site of profound scientific interest. Explorers Cove forams, which may normally have bathymetric ranges to 3,000 m, are ideal for field and laboratory experimentation, and serve as useful model systems for studying the ecology and evolution of deep-sea assemblages. Just as a firm understanding of the protists is vital to developing a clear picture of earlyeukaryotic evolution, the key to the origin of Foraminifera lies in the study of the early branching allogromiids. An improved understanding of the relationships between early forams through multigene based molecular phylogenies is a goal of this project. Additionally, a more careful study of the "crown allogromiids" will illuminate the evolutionary steps that lead to the rotaliids, which dominate many shallow-water temperate environments and pelagic foram assemblages. Extant protists represent the modern products of ancient predatory (phagotrophic) prokaryotes. Protists are well known as consumers of microbiota, but the consumption of metazoans by protists, one focus of our studies on allogromiids, is not widely appreciated. As a result, the consequences of ancient predatory protists are rarely considered a major factor in the diversification of animals during the late Proterozoic/early Cambrian . This project will test hypothesis that predation on metazoans is widespread among basal forams, and if supported by analyses of the new protein-coding sequence data, then the role of these protists in Neoproterozoic ecosystems will need to be reevaluated. The objectives of the research are to: test the validity of the foram phylogenetic hypotheses currently based solely on single gene sequence data; examine the ultrastructure of representative members of allogromiid clades; explore the origin of polar forams using the new molecular phylogenetic and structural data; further examine the trophic strategies of allogromiids; and to determine if carnivory is a fundamental nutritional mode for basal forams, or a special derived character. Additional broader impacts of this research include training of underrepresented groups through both grass-roots efforts and formal participation in national federally funded education programs.

有孔虫（Foraminifera）是一种结构复杂、数量丰富且分布广泛的原生生物。Alogromiid有孔虫通常在深海和高纬度组合中占主导地位，并被认为积极地改造这些栖息地的沉积物。在大陆坡系统中也很常见，这对有机物质的再循环，从而对全球地球化学循环都很重要。大多数有孔虫生物学的研究都集中在物种从浅热带/温带环境，在那里他们已被证明采用不同的营养策略，从营养到后生动物食肉。作为深海底栖大型和小型动物的重要组成部分，更好地了解基性异育类的原位行为和摄食生物学对海洋科学具有重要意义。南极洲的探险家湾是目前地球上唯一一个生物学家可以使用水肺直接进入“深海般”生态系统并大量收集基底异格藻的地方;因此，它是一个具有深远科学意义的地点。探险家湾有孔虫的水深范围通常可达3 000米，是进行实地和实验室实验的理想之选，是研究深海生物组合生态和演变的有用模型系统。正如对原生生物的深入了解对于形成早期真核生物进化的清晰图景至关重要一样，有孔虫类起源的关键在于对早期分支异源有孔虫的研究。通过基于多基因的分子遗传学来更好地理解早期有孔虫之间的关系是这个项目的目标。此外，更仔细的研究“冠allogromiids”将阐明的进化步骤，导致rotaliids，其中占主导地位的许多浅水温带环境和远洋有孔虫组合。现存的原生生物是古代掠食性原核生物的现代产物。原生生物是众所周知的消费者的微生物群，但消费的后生动物的原生生物，我们的研究重点之一allogromiids，并没有得到广泛的赞赏。因此，古代掠食性原生动物的后果很少被认为是晚元古代/早寒武纪动物多样化的主要因素。该项目将测试假设，捕食后生动物是广泛的基础有孔虫，如果支持新的蛋白质编码序列数据的分析，那么这些原生生物在新元古代生态系统中的作用将需要重新评估。研究的目的是：检验目前仅基于单基因序列数据的有孔虫系统发育假说的有效性;检查异格有孔虫分支代表成员的超微结构;利用新的分子系统发育和结构数据探索极地有孔虫的起源;进一步研究异格有孔虫的营养策略;并确定肉食性是否是基有孔虫的基本营养模式，或一种特殊的衍生特征。这项研究的其他更广泛的影响包括通过基层努力和正式参与国家联邦资助的教育计划来培训代表性不足的群体。