Sea-ice Snow Microbial Communities’ Impact on Antarctic Bromocarbon Budgets and Processes

每年春天在南极大陆形成的臭氧空洞是人类活动的特征之一，特别是释放到大气中的CFC（制冷剂中的含氯氟烃）的生产。尽管1987年《蒙特利尔议定书》禁止氟氯化碳，但复苏速度比预期的要慢。据估计，溴化碳是造成平流层臭氧消耗的物质，最近也是低层大气中溴的来源。南极海冰中溴碳的来源是什么？这是造成臭氧空洞的化学物质的另一个来源吗？该项目将测试海冰中的溴碳是否由海冰、雪和两者之间的界面中发现的微藻和细菌产生和降解。该项目将收集一套海冰和雪的化学和生物测量数据，以确定溴碳浓度、与之相关的微生物活动以及参与溴碳代谢的细胞内基因和蛋白质。该项目有利于NSF扩大南极系统，生物区系和过程的基础知识，并提高南极系统，冰冻圈和生物体之间的相互作用的理解的目标。这项工作将于晚春在麦默多站进行，包括将集中在实验室的冰雪取样，以及测量藻类和细菌活动的24小时实验。控制溴碳代谢酶合成的基因在生物技术和生物修复中引起了人们的兴趣，包括修复紫外线辐射损伤皮肤的产品。该项目将对本科生进行化学和生物技术培训。主要研究人员将参加在西雅图的太平洋科学中心，每个周末约有10，000名参观者，他们将在那里开发一个项目特定的展览。这项研究将介绍与冰雪表面释放溴碳化合物有关的微生物活动，这些化合物已知会降解平流层臭氧。化学溴碳的估算将与宏基因组学和元蛋白质组学方法相结合，以了解雪和海冰中微生物的潜在作用。环境、化学和生物数据将通过多变量分析进行综合，并通过ANOVA分析研究中心和实验处理之间的显著差异。来自瑞典哥德堡大学的一名合作者将在溴碳分析方面开展合作。这项研究还将涉及“盐雪”，这是一种以前没有研究过微生物生命的新环境。此外，这是首次在冰雪中进行元蛋白质组学研究。 主要研究人员希望他们的研究结果将有助于在21世纪为臭氧洞的恢复提供信息。该奖项反映了NSF的法定使命，并被认为值得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来支持。

The ozone hole that develops over the Antarctic continent every spring is one of the features attributed to human activity, in particular production of the CFC (chlorofluorocarbons in refrigerants) released to the atmosphere. In spite of the CFC ban from the Montreal Protocol established in the year 1987, the recovery has been slower than predicted. Bromocarbons, known to produce the stratospheric ozone depletion, have recently been estimated to contribute to the pool of bromines in the lower atmosphere. What is the origin of the bromocarbons in Antarctic sea ice? Is this an additional source of chemicals creating the ozone hole? This project will test if bromocarbons in sea ice are produced and degraded by microalgae and bacteria found in sea ice, in snow and the interface between the two. The project will collect a suite of chemical and biological measurements of sea ice and snow to determine bromocarbon concentrations, microbial activity associated with them, and intra-cellular genes and proteins involved in bromocarbon metabolism. This project benefits NSF’s goals of expanding fundamental knowledge of Antarctic systems, biota, and processes, and improving the understanding of interactions among the Antarctic systems, cryosphere and organisms. The work will be carried out at McMurdo Station in late austral spring, including sampling of snow and ice that will be concentrated in the laboratory, and 24-hour experiments to measure algal and bacterial activity. Genes controlling synthesis of enzymes involved in bromocarbon metabolism are of interest in biotechnology and bioremediation, including products that repair damaged skin from UltraViolet Radiation. The project will train undergraduate students on chemical and biological techniques. The Principal Investigators will be involved in the Pacific Science Center in Seattle with ~10,000 visitors per weekend where they will develop a project-specific exhibit.The microbial processes in snow and ice associated with bromocarbon synthesis and degradation have not been studied in Antarctica during winter and spring. This study will inform about microbial activity in relation to the release of bromocarbons compounds from the snow and ice surfaces, compounds known to degrade stratospheric ozone. The estimation of chemical bromocarbons will be combined with metagenomics and metaproteomics approaches for understanding the potential role of microbes in snow and sea ice. The environmental, chemical and biological data will be synthesized with multivariate analysis and significant differences between sites and experimental treatments with ANOVA. A collaborator from the University of Goteborg in Sweden will collaborate on bromocarbon analyses. The study will also address “saline snow” a new environment not previously studied for microbial life. In addition, this is the first study of meta-proteomics in snow and ice. The Principal Investigators expect their results will help inform ozone hole recovery in the 21st century.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.