The Fate of Microbial Life Encased in Sea Ice: Tracking Organisms and Survival Strategies Through the Arctic Winter

海冰中微生物生命的命运：在北极冬季追踪生物体和生存策略

• 批准号: 0327244
• 负责人: Jody Deming
• 金额: $ 28.13万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0327244&HistoricalAwards=false
• 关键词: Fate; Microbial; Life; Encased; Sea

Abstract of Deming ProposalEvery fall, open coastal waters of the high Arctic begin to close again as atmospheric temperature drops and sea ice forms. Organisms trapped in fluid inclusions of the ice are then held captive to increasingly severe temperature and salt concentration (typically to .20degrees C and ~20% salt) as winter progresses. The few microbial studies of winter sea ice have shown that cold-adapted (psychrophilic) heterotrophic bacteria are readily cultured from it, that metabolically active cells are associated with particulate matter in the brines, and that exopolymeric substances (EPS) may serve as cryoprotectants and a stable matrix for embedded bacteria. The fate of specific microorganisms, populations or communities during the long dark winter of the high Arctic, however, is unknown; their strategies for acquiring adequate nutrition under extreme conditions, the subject only of speculation. This project proposes to track microbial succession, at regular intervals and in vertical profile within the ice sheet, through the winter season at an established, interdisciplinary study site. Fluorescent probes will be used in quantitative, in situ hybridization analyses of ice sections, melted in isothermal-isohaline solutions. Diversity in selected samples will be further evaluated by 16S rRNA-based environmental cloning. The domain Archaea and division Cytophaga-Flavobacteria-Bacteriodes will be probed as endmember populations (expected to be low and high, respectively) and members of the psychrophilic genus, Colwellia, as representatives of culturable inhabitants. The latter are also selected due to completion of the whole-genome sequence of C. psychrerythraea strain 34H, the first psychrophilic organism to be sequenced. Available knowledge leads to the hypothesis that extracellular proteolytic enzyme activity in brine inclusions is stabilized by EPS, enabling a supply of nitrogen-rich organic compounds to heterotrophic bacteria as fuel for the winter. This concept and related ideas will be tested via in situ incubations in the ice sheet, using strain 34H and preparations of its extracellular proteases and exopolymers as amendments to sea-ice brines. The research platform will be the Canadian icebreaker, John Franklin, newly renovated for science operations in winter. The Franklin will be frozen into Franklin Bay (at the western entrance of the Northwest Passage, Canadian Archipelago) during winter 2003.2004 as part of a remarkable yearlong expedition in the region for the international Canadian Arctic Shelf Exchange Study (CASES). Results from this project will be interpreted within a strong interdisciplinary framework, given the CASES platform. Better understanding of microbial succession during winter and links to organic compounds in the ice will clarify spring conditions for carbon flux, from ice to ocean below, which can be significant regionally and globally. Environmental data on Colwellia will set the stage for sophisticated genome-based research in future. Results of in situ tests of winter survival hypotheses will provide basic knowledge applicable to more practical issues of societal interest concerning use of organisms, enzymes and other sensitive organic compounds under freezing conditions in the biomedical, aquaculture and food industries. The CASES overwintering expedition provides a unique educational and training opportunity for all involved. Participants from many countries, local Inuit villages and K-12 classrooms will be aboard the Franklin for joint field, laboratory, interdisciplinary and cross-cultural research and training. Results will be published in the peer-reviewed literature, incorporated into teaching efforts, and disseminated in venues designed to reach much broader audiences, including news and information releases from sea and video documentation of field and shipboard experiences for public viewing.

德明建议摘要每年秋天，由于大气温度下降和海冰形成，北极高纬度地区的开放沿海沃茨开始再次关闭。 随着冬季的到来，被困在冰的流体包裹体中的生物会被越来越苛刻的温度和盐浓度（通常为0.20摄氏度和~20%的盐）所俘虏。 冬季海冰的微生物研究表明，冷适应（嗜冷）异养细菌很容易培养出来，代谢活性细胞与盐水中的颗粒物质有关，外聚合物（EPS）可以作为冷冻保护剂和包埋细菌的稳定基质。 然而，在北极高纬度地区漫长黑暗的冬季，特定微生物、种群或群落的命运尚不清楚;它们在极端条件下获得充足营养的策略只是猜测的对象。 该项目建议在一个既定的跨学科研究地点，以固定的间隔和冰盖内的垂直剖面跟踪微生物的演替。 荧光探针将用于定量，原位杂交分析的冰部分，融化在等温等盐溶液。 将通过基于16 S rRNA的环境克隆进一步评估选定样品的多样性。 将探讨的结构域degreea和部门Cytophaga-Flavobacteria-Bacteriodes作为端员人口（预计将分别为低和高）和成员的嗜冷属，Colwellia，作为可培养的居民的代表。 后者也是由于C. psychryrythraea菌株34 H，第一个被测序的嗜冷生物。 现有的知识导致的假设，即胞外蛋白水解酶活性的盐水夹杂物是稳定的EPS，使富氮的有机化合物的供应异养细菌作为燃料的冬天。 这一概念和相关的想法将通过在冰盖中原位孵育进行测试，使用菌株34 H及其胞外蛋白酶和外聚合物的制剂作为海冰盐水的修正物。 研究平台将是加拿大破冰船约翰富兰克林，新装修的科学行动在冬季。 “富兰克林号”将于2003年至2004年冬季被冻入富兰克林湾（加拿大群岛西北航道的西入口处），这是为国际加拿大北极大陆架交换研究在该地区进行的为期一年的出色考察的一部分。该项目的结果将在一个强大的跨学科框架内进行解释，给出了案例平台。 更好地了解冬季微生物的演替以及与冰中有机化合物的联系，将有助于阐明春季碳通量的条件，从冰到下面的海洋，这在区域和全球范围内都具有重要意义。 Colwellia的环境数据将为未来基于基因组的复杂研究奠定基础。 冬季生存假设的现场测试结果将提供基本知识，适用于更实际的社会利益问题，涉及生物医学，水产养殖和食品工业在冷冻条件下使用生物，酶和其他敏感的有机化合物。 CASES越冬探险为所有参与者提供了一个独特的教育和培训机会。 来自许多国家、当地因纽特人村庄和K-12教室的参与者将登上富兰克林号，进行联合实地、实验室、跨学科和跨文化研究和培训。 研究结果将发表在同行审查的文献中，纳入教学工作，并在旨在接触更广泛受众的场所传播，包括发布海上新闻和信息以及提供现场和船上经验的视频文件，供公众观看。