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

该计划有两个主要目标：1）确定暴露于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颗粒对海冰融化行为的影响。这项研究将发展和应用最先进的微生物、分子、地球化学和地球物理技术，在阿拉斯加巴罗附近的实地考察融化季节结束时北极天然海冰的特征和演变。该项目将评估：（1）冰的物理特性（2）冰藻和细菌的特征（丰度、活性、生物量、生产力和多样性）;（3）聚合物凝胶特性（丰度、组成、凝胶碳生物量和大小）;（4）生物颗粒与冰物理特性的关系，特别是使用图像分析和相关统计方法对融化的和完整的冰样品的微结构特性进行研究。这一拟议项目将通过向一名本科生提供研究经验、指导一名博士后研究助理以及将相关科学成果纳入学术课程和公共宣传活动来开展教育宣传。

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.