Analysis of a Eukaryotic Microbial Mat Community Across Environmental Gradients in a Thermal, Acidic Stream

9977922黄石国家公园内Nymph Creek的真核微生物垫是微生物观测站的理想天然实验室，该观测站旨在增加我们对真核微生物遗传多样性、生态生理学和行为的理解。 在溪流源头附近的热（50摄氏度），酸性（pH 2.7）水在温度，pH值和光照方面产生稳定的环境梯度，微生物种群的变化将被监测。 该垫的生物复杂性是有限的附近流的来源，但包括红色的Cyanidium caldarium，已知的最嗜热菌，和嗜热，丝状真菌Dactylaria constricta变种。gallopava。随着下游pH值和水流量的增加以及温度的下降，预计微生物物种（包括黏菌、原生动物、绿色藻类和硅藻）的伴随扩张。两个若虫溪网站，定义在不同的光，pH值和温度方面，将广泛监测昼夜和季节性的时间段。现代分析，包括显微镜方法和rRNA测序，将用于记录微生物多样性和分析垫的微观结构在这两个网站。将记录大量水和通过垫的垂直方面的宏观和微观尺度环境条件的变化。 基于核酸序列的技术将用于在空间和时间变化的环境条件下原位监测微生物种群的变化。基于核糖体RNA序列的技术极大地促进了对自然环境中微生物的研究，并为微生物发生提供了一个合理的平台。然而，虽然这些方法通常用于研究未培养的细菌种群，但相同的方法尚未严格应用于真核微生物群落的研究。因此，新的真核生物物种的发现和真核微生物的多样性和生态生理学的理解，在很大程度上限制在培养菌株的描述。很明显，存在未培养的真核微生物，它们的发现可能代表了新微生物产品的巨大未开发来源。因此，深入研究，重点是真核微生物群落的生态学，通过基于核酸序列的检测和分类方法来增强，不能不从根本上推进这一领域的现有知识。从这项研究中获得的信息将包括新物种的描述，在纯培养的新菌株，和测量的遗传多样性及其与土著微生物的生态生理学的关系。 特别感兴趣的是C. caldarium和D.在20世纪70年代，布洛克和他的同事首次描述了这种真菌，他们发现这种真菌和真菌总是共存。 然而，他们没有详细说明这种相互作用，这种相互作用可能是共生的，寄生的，或者仅仅是巧合。 这对生物体可能代表了现代地衣的原始祖先，现代地衣通常由丝状真菌和绿色真菌组成。 深入的研究将探讨D.缢管线虫C.在一些情况下，研究人员还发现，藻类与高温藻的共生关系，包括高温藻是否为真菌提供营养，真菌是否寄生于高温藻，以及真菌菌丝是否提供锚定单细胞藻类和稳定河流沉积物的基质。真菌菌丝的黑色素也可以保护藻类免受强光的有害影响。此外，将培养通过rRNA测序在环境梯度中检测到的真菌或真菌的新基因型。真菌和藻类18S rRNA基因型的分布将决定是否独特的基因型与生态位。 Nymph Creek提供了一个可访问的室外实验室，研究人员，学生和公众可以在那里观察到形成繁茂明亮绿色微生物垫的微生物。来自Nymph Creek天文台的知识将通过外联和互联网活动分享。这些活动应提高公众对微生物多样性、生物化学微生物活动及其对生态系统的影响的认识和理解。

9977922The eukaryotic microbial mat at Nymph Creek in Yellowstone National Park is an ideal natural laboratory for a Microbial Observatory designed to increase our understanding of eukaryotic microbial genetic diversity, ecophysiology, and behavior. The thermal (50 degrees C), acidic (pH 2.7) water near the stream's source creates stable environmental gradients in temperature, pH, and light over which changes in microbial populations will be monitored. The mat's biocomplexity is limited near the stream's source but includes the red alga Cyanidium caldarium, the most thermophilic alga known, and the thermophilic, filamentous fungus Dactylaria constricta var. gallopava. As downstream pH and water flow increase and temperatures decline, a concomitant expansion of microbial species, including slime molds, protozoa, green algae, and diatoms, is expected. Two Nymph Creek sites, defined in terms of differing light, pH, and temperature, will be extensively monitored over diurnal and seasonal time periods. Contemporary analyses, including microscopic methods and rRNA sequencing, will be used to document microbial diversity and analyze the mat's microstructure at both sites. Changes in macro- and micro-scale environmental conditions in the bulk water and through the vertical aspect of the mats will be recorded. Nucleic acid sequence-based techniques will be used to monitor microbial population changes in situ under environmental conditions that vary in space and time. Ribosomal RNA sequence-based technologies greatly facilitate the study of microbes in natural environments and provide a rational platform on which to base phylogeny. However, while these methods are used routinely to study uncultivated bacterial populations, the same approaches have not been rigorously applied to studies of eukaryotic microbial communities. As a result, the discovery of new eukaryotic species and an understanding of the diversity and ecophysiologies of eukaryotic microorganisms are largely restricted to descriptions of cultivated strains. It is clear that uncultivated eukaryotic microorganisms exist and their discovery may represent a vast untapped source of new microbial products. Therefore, an in-depth study, focused on the ecology of a eukaryotic microbial community, augmented by nucleic acid sequence-based methods of detection and classification, cannot fail to fundamentally advance current knowledge in this field. Information gained from this study will include descriptions of new species, novel strains in axenic culture, and measurements of genetic diversity and its relationship to the ecophysiologies of indigenous microorganisms. Of particular interest is the interaction between C. caldarium and D. constricta, first described in the 1970's by Brock and his coworkers, who found that the alga and the fungus always cohabit. However, they did not elaborate on this interaction, which could be symbiotic, parasitic, or merely coincidental. This pair of organisms may represent a primitive ancestor to modern-day lichens, which are usually composed of a filamentous fungus and a green alga. In-depth studies will explore possible features of the D. constricta-C. caldarium association, including whether the alga provides nutrients for the fungus, whether the fungus parasitizes the alga, and whether the fungal hyphae provide a matrix that anchors the unicellular algae and stabilizes stream sediment. Melanin of fungal hyphae may also protect algae from the harmful effects of intense light. In addition, new genotypes of the fungus or alga detected by rRNA sequencing across environmental gradients will be cultured. The distributions of fungal and algal 18S rRNA genotypes will determine whether unique genotypes correlate with ecological niches. Nymph Creek provides an accessible outdoor laboratory where microbes that form luxuriant bright green microbial mats can be observed by researchers, students and the public. Knowledge from the Nymph Creek observatory will be shared via outreach and internet activities. These activities should increase public awareness and appreciation of microbial diversity, biochemical microbial activities, and their influences on ecosystems.