High Resolution Genomic and Proteomic Analyses of a Microbial Transport Mechanism from Antarctic Marine Waters to Permanent Snowpack

相对原始的南极大陆及其广阔的海洋区域代表了地球上调查海洋微生物长距离空中运输和沉积的独特位置。每年冬天在大陆周围形成的大面积新海冰导致大量的霜花，这是一种高盐含量的精致冰晶结构，形成于冰的表面，很容易被风吹散。这项拟议的研究建立在北极早期工作的基础上，并测试了一个新的假设，即风传播的霜花为海洋细菌的长距离运输提供了一种有效的机制，这种机制可以通过南极地区的霜花盐特征来独特地来源和跟踪。在运输路径的每个阶段都将获得微生物群落的高分辨率基因组快照，这将跟踪海洋微生物群落的减少部分，因为它冻结成海冰，融入霜花，转化为气溶胶，并最终沉积在大陆积雪中。在从海冰到积雪的过程中，海洋细菌将暴露在一系列环境压力下，包括高盐度、低温、紫外线和潜在的干燥。平行的蛋白质组学分析将能够评估微生物对这些极端条件的反应和潜在的生存机制，这些机制允许南极洲沉积地点的持久性或最终殖民化。目前对南极大气中微生物的了解是基于有限数量的显微镜和培养分析以及低分辨率16S RNA基因序列分析的单一报告。该研究将广泛影响对大气微生物学的理解，从来源到沉积，以及极端条件下微生物生存，定植，特有性和多样性的各种问题。除了到达科学界的场地外，研究小组还将开发一个关于南极微生物运输的永久性多媒体和人工制品展览，该展览将在西雅图的太平洋科学中心（PSC）展出，该中心每年教育近100万游客。

The relatively pristine Antarctic continent with its extensive maritime zone represents a unique location on the planet to investigate the long distance aerial transport and deposition of marine microorganisms. The vast extent of new sea ice that forms each winter around the continent results in large numbers of frost flowers, delicate ice-crystal structures of high salt content that form on the surface of the ice and are readily dispersed by wind. The proposed research builds on earlier work in the Arctic and tests the new hypothesis that wind-borne frost flowers provide an effective mechanism for the transport of marine bacteria over long distances, one that can be uniquely sourced and tracked by the frost flower salt signature in the Antarctic realm. A highly resolved genomic snapshot of the microbial community will be acquired at each stage in the transport path, which will track decreasing fractions of the marine microbial community as it freezes into sea ice, incorporates into frost flowers, converts to aerosols, and ultimately deposits within continental snowpack. En route from sea ice to snowpack, marine bacteria will be exposed to an array of environmental stresses, including high salinity, low temperatures, UV light and potential desiccation. A parallel proteomic analysis will enable an evaluation of the microbial response to these extreme conditions and potential survival mechanisms that allow persistence or eventual colonization of deposition sites across Antarctica. Current understanding of microbes in the Antarctic atmosphere is based on a limited number of microscopic and culture-based assays and a single report of low-resolution 16S RNA gene sequence analysis. The research will broadly impact understanding of atmospheric microbiology, from source to deposition, and various issues of microbial survival, colonization, endemism, and diversity under extreme conditions. In addition to venues that reach the scientific community, the research team will develop a permanent multi-media and artifact-based exhibit on Antarctic Microbial Transport that will be showcased at Seattle's Pacific Science Center (PSC), which educates nearly a million visitors annually.