RAPID: Investigation of Microbial:Black Carbon feedback Processes that Impact Icefield Melt in High Latitude Systems.

太阳辐射是冰川冰雪融化的主要驱动力。因此，冰川和高海拔山区积雪对吸收光粒子浓度的微小变化尤其敏感。如果矿物粉尘和有机物等杂质大量存在，那么雪和冰川冰的表面融水就会大大增加。细菌和藻类通过以生物膜的形式聚集这些杂质，进一步促进了冰川表面的变暗和融化。像阿拉斯加地区的许多高山冰川一样，朱诺冰原已经经历了大规模的质量损失。仅在2005年至2019年期间，就有63座冰川消失。模型预测，到21世纪中叶，整个冰原将呈现负质量平衡，地表融化可能是阿拉斯加冰川损失的驱动机制。人类和自然活动释放的黑碳已成为减少冰雪反照率的主要因素。微生物可以影响冰川表面黑碳的动态，其生物降解对其停留时间、吸光性以及向邻近和下游水生生态系统的输出具有深远的影响。拟议的研究利用了太平洋西北国家实验室（PNNL）的用户科学设施整合合作（FICUS）资助。FICUS提供的分析支持、最先进的仪器和专业知识将加快这一及时研究的速度。拟议研究的目标是确定(i)由黑碳沉积引起的冰川碳循环的人为扰动和（ii）微生物对黑碳的降解和转化。该项目支持必要的实地工作和相关费用、传播结果的资源以及学生参与样本分析。鉴于朱诺冰原对冰损失的敏感性以及对社会和环境的广泛影响，探索黑碳-微生物处理与冰损失之间的关系以及确定这些复杂的相互作用如何塑造冰原和冰川环境的命运是及时和相关的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Solar radiation is a primary driver of melting glacial ice and snow. Glaciers and high-elevation mountain snowpacks are therefore especially sensitive to even small changes in the concentration of light absorbing particles. Surface melt of snow and glacial ice is substantially higher if impurities such as mineral dust and organic matter are present in significant quantities. Bacteria and algae further promote darkening of the glacial surface and melting by aggregating these impurities in the form of biofilm. Like many mountain glaciers of the Alaskan region, the Juneau Icefield has seen extensive mass loss. Between 2005-2019 alone, sixty-three glaciers have disappeared. Models predict that the entire icefield will display a negative mass balance by the mid-21st century, with surface melt likely the driving mechanism of Alaskan glacier loss. Black carbon released by human and natural activities has become a major contributor to reducing snow and ice albedo. Microbes can affect the dynamics of black carbon on glacial surfaces, with biodegradation having profound implications on its residence time, light absorbance, and output to adjacent and downstream aquatic ecosystems.The proposed research leverages a Facilities Integrating Collaborations for User Science (FICUS) grant from Pacific Northwest National Laboratory (PNNL). The analytical support, access to state-of-the-art instrumentation, and expertise provided by the FICUS award will accelerate the speed of this timely research. The goals of the proposed study are to determine (i) the anthropogenic perturbation of the glacial carbon cycle due to black carbon depositions and (ii) degradation and transformation of black carbon by microbes. This project supports the necessary field work and associated costs, resources to disseminate results, and student involvement in sample analysis. Given the demonstrated sensitivity of the Juneau Icefields to ice loss and the broad implications for society and the environment it is timely and relevant to explore the relationship between black carbon-microbial processing-and ice loss, as well as determine how these complex interactions shape the fate of ice field and glacial environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.