Proteomic evidence of microbial weathering processes beneath the Greenland Ice Sheet

格陵兰冰盖(GRIS)的融化正在增加。与之相关的向邻近海洋的径流可能对海洋生态系统产生重要影响。融水的特征，如铁、硫酸盐和碳的含量，还不是很清楚，取决于冰盖下风化反应的程度和活动。这些关键冰下环境中的微生物是化学风化过程的重要贡献者，然而，迄今为止，这种过程的直接分子证据仍有待从GRIS冰下环境中获得。在这里，首席研究人员建议优化方法，分析以前从GRIS冰下融化水中获得的样品，并确定GRIS中微生物活动的证据？冰川下融化的水。该项目将通过为本科生提供研究经验，并为女性博士后研究人员提供指导，为STEM人力资源开发做出贡献。其专注于K-12的公众推广活动包括在西雅图S太平洋科学中心(极地科学、生命科学研究和UW PAWS on Science)为参观博物馆的公众提供三个年度科学周末体验的研讨会和展品。每一次活动都提供了与9000多名来自不同社会经济背景的学生进行一对一互动的可能性，让学生有时间在解释格陵兰冰微生物？这项工作最终将为GRIS下的酶微生物介导的营养循环和再矿化(例如，铁、硫酸盐、碳的释放)提供第一个直接的分子证据。这是改进微生物GRIS风化及其对未来极地海洋营养物质通量的影响的概念模型的关键的第一步。具体地说，首席研究员预计它将：1.优化冰下融水样品的蛋白质提取和环境蛋白质组学技术；2.确定与微生物风化和向海洋释放营养物质有关的酶；3.破译帮助冰下环境中微生物生存的分子保护机制；4.确定蛋白质/多肽生物标记物，以在未来的冰下研究中识别和量化关键的代谢过程；以及5.促进进一步发现环境生态学家和工业科学家非常感兴趣的新的冷适应酶。通过这些努力，PIS将展示探测酶控制的风化作用的能力，这是在实地详细量化和跟踪这些过程的先决条件(例如，通过将地球化学测量与有针对性的定量蛋白质组学和13C同位素示踪研究相结合)。该项目的成功有可能从根本上改变科学看待冰盖融化影响的方式。确定和量化控制风化和养分可获得性的微生物过程对于下一代概念模型冰盖-海洋相互作用至关重要。

Greenland Ice Sheet (GrIS) melting is increasing. The associated runoff to the adjacent oceans may have important impacts on marine ecosystems. Meltwater characteristics, such as iron, sulfate and carbon content, are not well known and depend on the extent and activity of weathering reactions beneath the ice sheet. Microbes in these critical subglacial environments are important contributors of chemical weathering processes, yet, to date, direct molecular evidence of such processes remains to be obtained from GrIS subglacial environments. Here, the principal investigators propose to optimize methods to analyze samples obtained previously from GrIS subglacial meltwaters and to identify evidence of microbial activity in GrIS? subglacial meltwaters. This is necessary background information required to develop models of the potential impact of increasing meltwater discharge from GrIS on local and downstream commercial fisheries.This project will contribute to STEM manpower development by offering research experience to an undergraduate student and mentoring to a female postdoctoral researcher. Its public K-12 focused outreach efforts include workshops and exhibits at three annual Science Weekend experiences for the museum-going public at Seattle?s Pacific Science Center (Polar Science, Life Science Research, and UW PAWS on Science). Each event provides the possibility of one-on-one interactions with over 9000 students from diverse socio-economic backgrounds, allowing time to excite students during explanation of the ?Greenland ice microbes? exhibit and presentation of a hands-on mass spectrometry model.This work will ultimately provide the first direct molecular evidence for enzymatic microbe-mediated nutrient cycling and remineralization (e.g., iron, sulfate, carbon release) underneath the GrIS. It constitutes the critical first step towards improving conceptual models of microbial GrIS weathering and its resulting impact on nutrient fluxes to future polar oceans. Specifically, the principal investigator anticipates that it will:1. Optimize protein extraction and environmental proteomics techniques for subglacial meltwater samples;2. Identify enzymes involved in microbial weathering and nutrient release to the ocean;3. Decipher molecular protective mechanisms that help microbes in the subglacial environment survive;4. Identify protein/peptide biomarkers to identify and quantify key metabolic processes in future subglacial studies; and5. Promote further discovery of novel cold-adaptive enzymes of significant interest toenvironmental ecologists and industrial scientists.Through these efforts, the PIs will demonstrate the ability to detect enzyme-controlled weathering, a prerequisite to quantify and track these processes in detail in the field (e.g., by combining geochemical measurements with targeted quantitative proteomics and 13C-isotopic tracer studies). The success of this project has the potential to fundamentally change the way in which science views the effects of ice sheet melting. Identification and quantification of the microbial processes controlling weathering and nutrient availability is critical to the next generation of conceptual models ice sheet-ocean interaction.