Microbial community shifts associated with rapid climate change during the transition between recent geological epochs

在2002年《自然》杂志的一篇评论文章中，保罗·克鲁岑认为，人类驱动的气候变暖导致了地质时代的转变，从全新世(H)转向被称为人类世(A)的新纪元。这种转变至少与大约11500年前从最后一个冰河时代(P)到现代冰河时代(H)的转变一样戏剧性，如果不是更戏剧性的话。由于冰冻圈在调节高纬度生态系统方面的重要性，北方特别容易受到气候影响的影响。此外，北极变暖的速度比全球平均地表温度上升的速度快两到三倍，这一效应被称为极地放大。微生物是北极系统的重要驱动力，在养分循环以及碳周转和储存中发挥重要作用，也是通过微生物群落结构的演替发展来指示生态系统变化的指标。因此，微生物群落可以洞察不断变化的北方环境中生态系统功能和结构的变化。我的长期目标是确定微生物群落对北极变暖的反应。在这个拟议的研究计划中，我计划阐明在不同地质时代之间的过渡期间，由于气候变化，北方微生物群落的结构和功能是如何变化的。我将通过以下方式回答这些问题：1.描述P/H转变时现存和灭绝的微生物群落的变化，这类似于当前快速的气候变化。2.表征现代微生物群落对冰川退缩和冰下环境暴露的响应。3.确定主导地位从厚实的多年老海冰向薄的第一年新海冰的转变对北冰洋微生物海冰群落的影响。*我将培训两名博士生和四名理科硕士。学生以及5-10名本科生研究助理。这些项目将是独立的，但将在实地和实验室使用类似的工具和技术。所有学生都将与彼此以及与合作者密切互动。在野外，我们将使用合理的生态样本设计，良好的日期和特征的野外场地和条件，以及移植实验，以获得理想的样本，为我们的方法。我们将使用标准方法和气体流量分析来广泛地表征环境条件。我们将利用元基因组学方法来描述和比较微生物群落的结构和功能。其结果将是气候、当地环境和历史条件以及微生物群落结构和功能相互作用的详细表征，这将从根本上增强我们对土壤微生物群落对不同地质时代交界处快速变化的环境的响应的了解。

In a 2002 Nature commentary, Paul Crutzen argued that human-driven climate warming has resulted in a shift in geological epochs, from the Holocene (H) to a new epoch dubbed the Anthropocene (A). This shift is at least as dramatic as, if not more so than, the shift about 11,500 years ago from the last ice age (P) to the modern (H). Due to the importance of the cryosphere in regulating high latitude ecosystems, the North is particularly susceptible to climate effects. Furthermore, warming in the Arctic is occurring two to three times faster than the increase in global mean surface temperatures, an effect known as polar amplification. Microorganisms are important drivers in Arctic systems, playing significant roles in nutrient cycling as well as carbon turnover and storage, and are also indicators of ecosystem changes through successional development of microbial community structure. As such, microbial communities can provide insight into changes in both ecosystem function and structure in a changing Northern environment.******My long-term objective is to determine the response of microbial communities to warming in the Arctic. Within this proposed research program, I plan to clarify how the structure and function of Northern microbial communities shift as a result of changing climate during the transition between different geological epochs. I will address these questions by: 1. Characterizing the extant and extinct microbial community shifts at the P/H transition, an analogue for current rapid climate change. 2. Characterizing modern microbial community response to glacier retreat and exposure of subglacial environments. 3. Determining the impact of a shift in dominance from thick, old multi-year sea ice to a thin, young first year sea ice on Arctic Ocean microbial sea ice communities.******I will be training two Ph.D. students and four M.Sc. students as well as 5-10 undergraduate research assistants. These projects will be independent, but will utilize similar tools and techniques, both in the field and in the laboratory. All students will interact closely with each other and with collaborators. In the field, we will use sound ecological sample design, well-dated and characterized field sites and conditions, and transplant experiments to obtain the ideal samples for our approach. We will characterize the environmental conditions extensively using standard approaches and gas flux analyses. We will utilize metagenomic approaches to characterize and compare microbial community structure and function. The result will be a detailed characterization of the interaction of climate, local environmental and historical conditions, and microbial community structure and function that will fundamentally enhance our knowledge of the response of soil microbial communities to a rapidly changing environment at the border between different geological epochs.