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

每年春天在南极大陆上空形成的臭氧空洞是人类活动的特征之一，特别是排放到大气中的氟氯化碳(制冷剂中的氯氟烃)的产生。尽管1987年制定的《蒙特利尔议定书》禁止使用氯氟化碳，但恢复的速度比预期的要慢。已知会造成平流层臭氧消耗的溴碳，最近被估计对低层大气中的溴池有贡献。南极海冰中溴碳的来源是什么？这是造成臭氧层空洞的另一个化学物质来源吗？该项目将测试海冰中的溴碳是否由海冰、雪中以及两者之间的界面上发现的微藻和细菌产生和降解。该项目将收集一套海洋冰雪的化学和生物测量，以确定溴碳浓度、与其相关的微生物活动以及参与溴碳新陈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、生物群和过程的基础知识，并提高对南极系统、冰冻圈和生物体之间相互作用的理解。这项工作将于春季末在麦克默多站进行，包括对将在实验室集中的雪和冰进行采样，以及24小时测量藻类和细菌活动的实验。控制与溴碳代谢有关的酶的合成的基因在生物技术和生物修复方面很有兴趣，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方面的培训。首席调查人员将参与西雅图太平洋科学中心的工作，每个周末有大约10,000名参观者，他们将在那里开发一个特定于项目的展览。在南极洲的冬季和春季，与溴碳合成和降解相关的冰雪微生物过程尚未被研究。这项研究将介绍与冰雪表面释放的溴碳化合物有关的微生物活动，这些化合物已知能降解平流层臭氧。对化学溴碳的估计将与总基因组学和总蛋白质组学方法相结合，以了解微生物在雪和海冰中的潜在作用。环境、化学和生物数据将通过多变量分析和地点之间的显著差异和实验处理之间的方差分析来综合。瑞典哥德堡大学的一名合作者将在溴碳分析方面进行合作。这项研究还将解决“盐碱雪”问题，这是一种以前没有对微生物生命进行研究的新环境。此外，这是第一次对冰雪中的超蛋白质组学进行研究。首席调查人员预计他们的结果将有助于在21世纪恢复臭氧空洞。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.