Extreme summer melt: Assessing the habitability and physical structure of rotting first-year Arctic sea ice

该建议有两个主要目标：1)确定严重融化的海冰的物理和微生物特征以及微结构演变；2)探索海冰藻类、细菌和聚合物凝胶等生物粒子对海冰融化行为的影响。这项研究将开发和应用最先进的微生物学、分子、生物地球化学和地球物理技术，以检查阿拉斯加巴罗附近野外地点融化季节结束时北冰洋天然海冰的特征和演变。该项目将评估：(1)使用标准和新的显微镜和X射线计算机断层扫描技术的冰物理特征(冰密度、盐度、渗透性、反照率和微结构)；(2)使用荧光和共聚焦显微镜、流式细胞仪和大规模平行Taq测序技术评估冰藻和细菌的特征(丰度、活性、生物量、生产力和多样性)；(3)使用原位显微镜、流式细胞仪和共聚焦显微镜技术评估聚合物凝胶特征(丰度、组成、凝胶碳生物量和大小)；(4)利用图像分析和相关统计方法对融化冰样和完整冰样的生物微粒与冰物理特性，特别是微结构特性之间的关系进行了研究。这一拟议项目将通过向本科生提供研究经验，指导博士后研究助理，并将相关科学成果纳入学术课程和公共宣传，来开展教育推广。

This proposal has two main objectives: 1) determination of the physical and microbial characteristics and microstructural evolution of sea ice exposed to severe melt; and 2) exploration of the influence of biogenic particles such as sea ice algae, bacteria and polymer gels on the melting behavior of sea ice. This research will develop and apply state-of-the-art microbiological, molecular, biogeochemical and geophysical techniques to examine the character and evolution of natural Arctic sea ice at the end of the melt season at field sites near Barrow, Alaska. This project will assess: (1) ice physical characteristics (ice density, salinity, permeability, albedo, and microstructure) using standard and novel microscopy and X-ray computed tomography techniques; (2) ice algal and bacterial characteristics (abundance, activity, biomass, productivity and diversity) using epifluorescence and confocal microscopy, flow cytometry and massively parallel taq sequencing techniques; (3) polymer gel characteristics (abundance, composition, gel carbon biomass, and size) using in situ microscopy, flow cytometry and confocal microscopy techniques; and (4) the relationship between biogenic particles and ice physical characteristics, in particular microstructural properties for melted and intact ice samples using image analysis and correlative statistical methods. This proposed project will carry out educational outreach by offering research experience to an undergraduate student, mentoring a postdoctoral research associate, and entrainment of relevant scientific results into both academic curricula and public outreach.