LEXEN: Biodiversity of Microorganisms in Ancient Polar Ice

在格陵兰岛和南极洲的极地冰深核样本中，可以发现数量惊人、种类繁多的微生物，其历史可能可以追溯到25万年前。尽管最近在这块古老的冰层样本中发现了丝状真菌、酵母菌、细菌和一种植物病毒，但这些冰芯的微生物系统调查尚未进行。这些发现证实了这样一种观点，即冰川(极地)冰是一种天然的空气采样机制，它在地质时代捕获了风传播的微生物。这些生物(代表极地特有的类群，以及来自温带和热带地区的外来物种)起源于海浪作用产生的气溶胶、风媒花粉和土壤颗粒、受感染的植物表面和许多其他来源。因此，冰川冰提供了一个独特的全球微生物来源，呈现了当代和古代真菌、细菌和病毒多样性的景象。这项工作的主要目标是表征古代真菌、细菌和病毒群落中的微生物生物多样性，以便与当代物种进行比较研究。具体目标是：确定和描述困在冰川冰中的特有和外来真菌、细菌和病毒的特征；确定格陵兰和南极洲相同年龄的冰中的真菌、细菌和病毒；研究选定的持久性物种的系统发育和寿命。这项研究的一个潜在目标是利用上述剖面来比较各种真菌、细菌和病毒的相对比例，并将它们与环境特征(气候条件、硫化作用等)相关联。在每个时间点。有待检验的假设是：首先，在极地冰层中存在感染人类、动物、植物和细菌的病毒，并可以检测到这些病毒。其次，相同的真菌、细菌和病毒出现在格陵兰岛和南极洲相同年龄的冰层中。第三，特定的真菌、细菌和病毒(或它们的核酸)长期存在于冰中。从格陵兰岛和南极洲收集的岩心中连续更古老的冰层的轮廓将被用来检验假设。拟议的时间和空间分析将把对微生物生物多样性的评估扩展到地质时间范围。如果能够在两个极地地区收集的年龄相近的冰中检测到相同的微生物物种，作为全球分布的证据，那么它们可能会在随后的研究中用作全球气候变化以及地质和人类活动的生物指标。因此，两极研究是必不可少的。开发和测试的协议可能有助于未来在火星极地冰或最近发现的月球冰中寻找微生物。因此，为了进行比较，了解古代地球冰中存在哪些微生物将是至关重要的。

ABSTRACTRogers, Scott9808676A surprising number and variety of microorganisms can be recovered from the interior of deep-core samples of polar ice in Greenland and Antarctica, perhaps dating back 250, 000 years. Although filamentous fungi, yeast, bacteria, and a plant virus have recently been detected in samples of this ancient ice--carefully protected from modern contaminants--systematic surveys of these cores for microbes have not been conducted These discoveries confirm the opinion that glacial (polar) ice is a natural air-sampling mechanism, which has trapped wind-transported microorganisms through geological epochs. These organisms (representing taxa that are endemic to the polar regions, as well as exotics from temperate and tropical regions) originated from aerosols generated by sea wave action, wind-borne pollen and soil particles, infected plant surfaces, and many other sources. Thus, glacial ice provides a unique global source of microorganisms that presents a view of both contemporary and ancient fungal, bacteria!, and viral diversity.The main goal of this work is to characterize microbial biodiversity within ancient communities of fungi, bacteria, and viruses for comparative studies with contemporary species. Specific objectives are to: identify and characterize endemic and exotic fungi, bacteria, and viruses entrapped in glacial ice; identify those in ice of the same age from both Greenland and Antarctica; and study phylogeny and longevity in selected persistent species. A potential objective of this study is to use the above profiles to compare the relative proportions of the various fungi, bacteria, and viruses, and to correlate these with environmental characteristics (climatic conditions, vulcanism, etc.) at each of the time points. Hypotheses to be tested are: First, viruses that infect humans, animals, plants, and bacteria are present and can be detected in polar ice. Second, identical fungi, bacteria, and viruses occur in ice of the same age from Greenland and Antarctica. Third, specific fungi, bacteria, and viruses (or their nucleic acids) persist in ice over long periods of time.Profiles of successively older ice strata from cores collected in Greenland and Antarctica will be utilized to test the hypotheses. The proposed temporal and spatial analyses will extend the assessment of microbial biodiversity to geologic timeframes. If identical microbial species can be detected in ice of similar age collected from both polar regions, as evidence of global distribution, they might then be utilized in subsequent studies as bioindicators of global changes in climate, and geologic and human activity. Thus, bipolar studies are essential. The protocols developed and tested may contribute to future searches for microorganisms in Martian polar ice or recently discovered lunar ice. Therefore, for comparative purposes it will be essential to know what microorganisms are present in ancient Earth ice.