The development and function of subarctic alpine soil surface biological communities

亚北极高山土壤表层生物群落的发育与功能

• 批准号: RGPIN-2017-05285
• 负责人: Stewart, Katherine
• 金额: $ 3.35万
• 依托单位: University of Saskatchewan
• 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=765633
• 关键词: development; function; subarctic; alpine; soil

Due to their ubiquitous distribution and unique physiology, establishment of biological soil crust (BSC) communities and corresponding initiation of key ecosystem functions is a common early successional process. In alpine and arctic environments, BSCs are often a dominant vegetation unit, making these ecosystems a uniquely powerful model for examining the role of BSCs in terrestrial ecosystem development. My long-term goal is to identify mechanisms at the BSC-soil surface interface that drive nutrient cycling processes in arctic and alpine environments. BSCs are located at the soil-atmosphere interface where their developmental trajectories are driven by both microclimate and soil physicochemical factors. As these soil surface assemblages establish, they in turn modulate their environment through the initiation of key ecosystem functions at biogeochemical interfaces between BSCs and below-crust soils. Over the next 5 years my short-term goal is to link the realized niches of key BSC components with the initiation and modulation of nutrient cycling processes at the BSC-soil interface. My specific objectives are to: 1) develop successional models of BSC communities based upon the realized niche of primary macro and micro BSC phyla; 2) examine the development and function of BSC assemblages in relation to soil physical, chemical and microbial properties; and 3) relate BSC development to ecosystem-level nutrient cycling driven by BSC and below-crust soil microbial communities. Using glacial forefields (i.e. areas progressively exposed by a receding glacier) as ideal chronosequence systems, I will conduct both observational and manipulative investigations to determine and confirm the realized niche of key BSC components. In addition, I will use manipulative growth chamber experiments to more closely examine the interactions between BSCs and physical, chemical and microbial soil properties. To better characterize the role BSCs and below-crust soil microbial communities play in nutrient transfer and transformations, I will examine the uptake and movement of isotopically labelled C, N and P in microcosm studies. Nutrient movement both between ecosystem components (i.e. crusts, soils, above and belowground vascular plants), and BSC and below-crust soil microbial communities will be investigated. By determining how BSC communities develop and in turn modify the soil environment, the proposed research will advance our understanding of early successional processes and ability to restore pathways that promote long-term ecosystem health.

由于其无处不在的分布和独特的生理特性，生物结皮(BSC)群落的建立和关键生态系统功能的启动是一个常见的早期演替过程。在高山和北极环境中，生物干细胞往往是主要的植被单位，使这些生态系统成为研究生物干细胞在陆地生态系统发展中的作用的独特而强大的模型。我的长期目标是确定在BSC-土壤表面界面上驱动北极和高山环境中养分循环过程的机制。生物干细胞位于土壤-大气界面，其发育轨迹受小气候和土壤物理化学因素共同驱动。随着这些土壤表面组合的建立，它们反过来通过启动生物干细胞和结皮下土壤之间的生物地球化学界面上的关键生态系统功能来调节环境。在接下来的5年里，我的短期目标是将实现的关键BSC组件的生态位与启动和调节BSC-土壤界面的养分循环过程联系起来。我的具体目标是：1)基于实现的初级宏观和微观BSC门的生态位，建立BSC群落的演替模型；2)研究BSC组合的发展和功能与土壤物理、化学和微生物特性的关系；3)将BSC的发展与BSC和结皮下土壤微生物群落驱动的生态系统水平的养分循环联系起来。使用冰川前场(即被消退的冰川逐渐暴露的区域)作为理想的时间序列系统，我将进行观察性和操纵性调查，以确定和确认关键BSC组件的实现生态位。此外，我将使用操纵性生长室实验来更密切地研究BSCs与土壤物理、化学和微生物特性之间的相互作用。为了更好地表征生物干细胞和结皮下土壤微生物群落在养分转移和转化中所起的作用，我将在微观研究中检查同位素标记的C、N和P的吸收和移动。将调查生态系统组成部分(即结皮、土壤、地上和地下维管植物)之间以及生物多样性和结皮下土壤微生物群落之间的养分移动。通过确定BSC群落如何发展并进而改变土壤环境，拟议的研究将促进我们对早期演替过程的理解，以及恢复促进长期生态系统健康的途径的能力。