Seasonal Dynamics of Giant Agglutinated Foraminifera

本文对南极麦克默多海峡探险者湾的优势胶结有孔虫组合进行了季节性研究。 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10月、11月和12月初采集的标本。例如，在南极冬季之后和夏季之前，冰下和底栖初级生产力爆发。关于有孔虫对这个夏季食物脉冲的反应，几乎没有什么信息。 这项工作的目的是利用计划在该区域扩大的后勤支助。 该提案的具体目标是： 记录南极春季至夏末探险者湾底栖生物相关非生物和生物因素的变化;并描述凝集有孔虫群落结构（物种组成、密度、大小分布）的相应反应。这些第一个目标将通过传统的沉积物取芯、生物量测定和显微镜分选方法来实现。 此外，一个原位的方法记录使用新型水下显微镜设备的精细尺度的变化将被利用。 研究季节性有孔虫群落动态的分子工具最初集中在生殖事件的时间，多重裂变，配子发生将得到完善。 其他工作将侧重于新改进的沉积物芯嵌入方法，以探索有孔虫生命位置的细尺度季节变化。在相关的实验室实验中，将分析关键凝集物种的营养机制。 从新鲜采集的有孔虫和“速冻”有孔虫中提取的脂质的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现有食物来源而变化。这些结合的方法将导致更完整的理解较大的凝集有孔虫在探险家湾底栖食物网中所扮演的角色，以及这些角色如何随着夏季食物脉冲而变化。由于探险家湾及其胶结有孔虫组合与许多半深海和深海地点密切相关，这些研究的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.