Seasonal Dynamics of Giant Agglutinated Foraminifera

对南极麦克默多湾探险者湾占优势的凝集有孔虫组合的季节性研究是本研究的重点。研究表明，在这个地方的凝集有孔虫（“有孔虫”）消耗各种各样的猎物，从细菌到分类上多样化的后生动物，包括幼年无脊椎动物。这些研究仅限于在10月、11月和12月初收集的标本，即在南方冬季刚刚结束和冰下和底栖生物初级生产力在夏季爆发之前。关于有孔虫对夏季食物脉动的反应的信息很少。这项工作的目的是利用该地区计划的后勤支持扩展。本提案的具体目的是：记录南方春季至夏末探险家湾底栖生物中相关非生物和生物因素的变化；并对凝集有孔虫群落结构（物种组成、密度、大小分布）的响应进行表征。这些最初的目标将通过传统的沉积物取心、生物量测定和微观分选方法来实现。此外，将使用新型水下显微镜设备记录精细尺度变化的原位方法。研究季节性有孔虫群落动态的分子工具最初集中在繁殖事件的时间、多重裂变、配子体发生等方面。进一步的工作将集中在新改进的沉积物岩心嵌入方法上，以探索有孔虫生命位置的精细尺度季节性变化。在相关的实验室实验中，将分析关键凝集物种的营养机制。从新鲜采集和“快速冷冻”有孔虫中提取的脂质进行时间分辨稳定同位素分析，将用于确定这些机制是否以及如何响应可用的食物来源而发生变化。这些综合方法将使我们更全面地了解探险者湾底栖生物食物网中较大的凝集有孔虫所扮演的角色，以及这些角色是如何随着夏季食物脉动而变化的。由于探险者湾及其凝集有孔虫组合与许多深海和深海地区具有密切的可比性，这些研究结果将在海洋科学中具有广泛的意义。

A seasonal study of the dominant agglutinated foraminiferal assemblage in Explorers Cove, McMurdo Sound, Antarctica is the focus of this research. Studies have shown that the agglutinated foraminifera ("forams") at this locality consume a wide variety of prey, ranging from bacteria through a taxonomically diverse group of metazoans, including juvenile invertebrates. These studies have been restricted to specimens collected inOctober, November and early December, i. e., immediately following the Austral winter and beforethe summer burst of under-ice and benthic primary productivity. Little information is available regarding the foraminiferal response to this summer food pulse. The aim of this work is to utilize the planned extention of logistic support in the region. The Specific Aims of this proposal are: To document Austral spring to late- summer changes in relevant abiotic and biotic factors in the Explorers Cove benthos; and to characterize corresponding responses in agglutinated foram community structure (species composition, densities, size distribution). These first aims will be accomplished by traditional sediment coring, biomass determinations, and microscopic sorting methods. Additionally, an -situ approach for documenting fine-scale changes using novel underwater microscopy equipment will be utilized. Molecular tools to examine seasonal foram community dynamics initially focusing on the timing, of reproductive events multiple fission, gametogenesis will be perfected. Additional work will focus on newly refined sediment core embedding methods to explore the fine-scale seasonal changes in foram life position. In related lab experiments, the trophic mechanisms of the key agglutinated species will be analyzed. Time-resolved stable isotope analyses of lipids extracted from freshly collected and "snap frozen" forams will be used to determine if and how these mechanisms change in response to available food sources. These combined approaches will lead to a more complete understanding ofthe roles played by larger agglutinated forams in the Explorers Cove benthic food web, and how these roles change with respect to the summer food pulse. Because Explorers Cove and its agglutinated foram assemblage are closely comparable to many bathyal and abyssal deep-sea localities, the results of these studies will have wide significance in the ocean sciences.