Ecology and Evolution of Arctic Marine Microbial Communities

北极海洋微生物群落的生态和进化

• 批准号: RGPIN-2022-05280
• 负责人: Collins, Eric
• 金额: $ 2.04万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=753232
• 关键词: Ecology; Evolution; Arctic; Marine; Microbial

The defining characteristic of the Arctic Ocean is the thin layer of sea ice that has covered its surface more or less continuously for tens of millions of years. Marine microbes in Arctic seawater and sea ice (including bacteria, archaea, fungi, protists, algae, and viruses) have had millions of years to adapt to the extreme conditions there, including perennially subzero temperatures, high brine salinity, and long periods of extended darkness and daylight. However, in the last 40 years, that ice cover has started to melt. Arctic sea ice extent and volume have both declined precipitously, resulting in increased interests in shipping, exploration, and resource extraction in the now seasonally ice-free waters. While the Arctic Ocean is changing faster than any other environment on Earth, our observational efforts have not kept up. However, recent advances in high-throughput DNA sequencing have allowed the possibility of observing microbial communities at temporal and spatial scales that were unimaginable only a generation ago. The long term goal of my Discovery program is to take advantage of novel sequencing technologies to contribute to ecological and evolutionary models of Arctic marine microbial communities from an Ecosystem Services perspective, advancing our understanding of the effects of past, current and future climatic changes on these bellweather ecosystems. The specific Objectives of this 5-year Discovery proposal are (1) to identify genomic indicators of functional adaptation in microbial populations, and (2) to provide novel insights into microbial community succession in sea ice and seawater over numerous time scales. Objective (1) will lead to improvements in evolutionary models of Arctic marine microbes by greatly increasing the number of complete genomes available from these environments. Using long-read nanopore sequencing technology will enable the assembly of many closed, circular genomes for cold-adapted bacteria and archaea, which will be used to assess evolutionary models of functional and cold adaptation through comparative genomics, and insights into the role that horizontal gene transfer plays. Objective (2) will lead to improvements in ecological models of Arctic marine ecosystems by greatly increasing the temporal resolution by which community succession can be observed, which is typically sparse due to logistical difficulties. However, I will make use of a new Arctic research facility located on Hudson Bay, the Churchill Marine Observatory (CMO). This facility will provide year-round access to cold seawater, enabling high-temporal-resolution models of seawater microbial succession in response to temperature, salinity, light, nutrients, and ice dynamics. Likewise, I will obtain sea ice grown in large mesocosm tanks at CMO (10m x 10m x 3m) for analysis of rapid changes in microbial community structure resulting from freezing and melting dynamics, which have already been substantially altered by climate warming.

北极海洋的定义特征是海冰的薄层，它或多或少地覆盖了其表面，持续了数千万年。北极海水和海冰中的海洋微生物（包括细菌，古细菌，真菌，生物，藻类和病毒）已有数百万年的时间适应那里的极端条件，包括长期亚盐的温度，高盐水盐酸，高盐水和长时间的延长黑暗和日光。但是，在过去的40年中，冰盖开始融化。北极海冰范围和体积都在急剧下降，从而增加了现在无季节性水域的运输，勘探和资源提取的兴趣。尽管北极海的变化比地球上任何其他环境都要快，但我们的观察努力并没有跟上。但是，高通量DNA测序的最新进展使您可以在仅一代前就无法想象的临时和空间尺度上观察微生物群落。我的发现计划的长期目标是利用新颖的测序技术从生态系统服务的角度为北极海洋微生物群落的生态和进化模型做出贡献，从而促进了我们对过去，当前和未来气候变化对这些Bellweather生态系统的影响的理解。这项为期5年的发现建议的具体目标是（1）确定微生物种群功能适应的基因组指标，以及（2）在许多时间尺度上提供对海冰和海水中微生物群落继承的新见解。目标（1）将通过大大增加这些环境可用的完整基因组的数量来改善北极海洋微生物的进化模型。使用长阅读的纳米孔测序技术将使许多封闭的，冷适应的细菌和古细菌的封闭循环基因组组装，这些基因组将用于评估通过比较基因组学的功能和冷适应的进化模型，并洞悉水平基因转移的作用。目标（2）将通过大大增加可以观察到社区继任的临时分辨率，从而改善北极海洋生态系统的生态模型，这通常由于后勤困难而稀疏。但是，我将利用位于丘吉尔海洋天文台（CMO）哈德逊湾的新北极研究机构。该设施将全年提供冷海水的通道，从而使海水微生物成功的高速分辨率模型，以响应温度，盐度，光，营养和冰动力学。同样，我将获得在CMO（10m x 10m x 3M）的大型中库罐中生长的海冰，以分析因冻结和熔化动态而导致的微生物群落结构的快速变化，这已经通过气候变暖大大改变了。