Sea Ice Microbial Ecosystems in the Rapidly Changing Arctic

快速变化的北极海冰微生物生态系统

• 批准号: RGPIN-2020-05267
• 负责人: Hubert, Casey
• 金额: $ 2.4万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717359
• 关键词: Sea; Ice; Microbial; Ecosystems; Rapidly

Sea ice habitats are caught in the grip of climate change such that they are one of the most drastically changing environments on earth. Covering 10% of the global ocean, sea ice is currently in a period of transition with declining permanent multiyear ice' being replaced with increasing amounts of transient first year ice' that melts and refreezes annually. Microbial life in sea ice must therefore be adapted to extreme and rapidly changing conditions, yet very little is known about this microbiome. A complete picture of marine microbial ecology and biogeochemistry in the rapidly changing Arctic requires an improved understanding of the sea ice microbial communities, how they form, and what they do. In polar seas water begins to freeze when seawater temperatures drop below 2C. During sea ice formation salts are expelled and brine channels form amidst the solid ice. At lower temperatures the salinity in the brine channels can be tenfold greater than seawater. Liquid brines are suitable habitats for certain microorganisms, and sea ice has been shown to contain surprisingly high numbers of bacteria sometimes more than in surrounding seawater. Brine channel microbial community assembly is poorly understood, and likely involves environmental selection of seawater bacteria that are dormant or otherwise marginalized in that unfrozen setting, but that gain an advantage when they encounter colder and saltier conditions in winter sea ice brine channels. The longterm objective of the Geomicrobiology Group led by Dr. Hubert is to understand the distribution and ecophysiology of numerically rare organisms, some of them extremophiles, within microbial communities in the context of environmental change. In the face of environmental change, microbes are the first responders. The enormous microbial diversity present in natural environments is formed by many low abundance taxa, the so called rare biosphere'. Rare organisms might be dormant yet they are poised to respond rapidly if environmental conditions change. The microbiome in first year sea ice offers an exciting and timely opportunity to examine the microbial response to rapid environmental change. The increasing prominence of dynamic first year ice brings microbial community assembly and microbial seed bank' dynamics to the forefront of understanding marine microbial communities. Halopsychrophiles that may be rare and dormant in summer seawater become key players in winter ice brines as sub-zero temperatures and high salinity drive environmental selection.

海冰栖息地受到气候变化的影响，成为地球上变化最剧烈的环境之一。海冰覆盖了全球海洋的10%，目前正处于一个过渡时期，永久性多年冰的减少被每年融化和重新冻结的瞬态第一年冰的增加所取代。因此，海冰中的微生物必须适应极端和快速变化的条件，但对这种微生物群知之甚少。要全面了解快速变化的北极地区的海洋微生物生态和生物地球化学，就需要更好地了解海冰微生物群落，它们是如何形成的，以及它们的作用。