Structure and function of biocrusts in weathering, soil formation and erosion processes (CRUSTWEATHERING).

风化、土壤形成和侵蚀过程中生物结皮的结构和功能（CRUSTWEATHERING）。

• 批准号: 280661654
• 负责人: Professor Dr. Jörg Bendix
• 金额: --
• 依托单位: Fachgebiet Klimageographie und Umweltmodellierung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/280661654?language=en
• 关键词: Structure; function; biocrusts; weathering; soil

On a global scale, biological soil crusts (biocrusts) form the most productive microbial biomass of the Earth´ -Critical Zone- in arid regions. Biocrusts are formed by living organisms such as heterotrophic bacteria, fungi, lichens, bryophytes, cyanobacteria and algae and their by-products, creating a top-soil layer of inorganic particles bound together by organic materials. They can be characterized as ecosystem-engineers forming water-stable, aggregated surface layers that have important multi-functional ecological roles in primary production, mineralization, bioweathering, dust trapping, and the stabilization of soils, slopes and entire landscapes, thereby affecting the nutrient and hydrological cycles across scales. Intensive literature reviews made us aware, that these communities are almost unstudied in South America, although highly abundant in the study areas of the Priority Programme. Therefore, the objectives of this interdisciplinary proposal are to 1) evaluate the almost unknown community structure of Chilean biocrust types using a combination of field and laboratory methods to address the relative abundance of the full spectrum of biocrust organisms, particularly with regard to their role in weathering and landscape forming processes (who is doing what?); 2) disclose which of the abundant organisms contribute by which biochemical processes to bioweathering, and quantify the reaction rates in relation to community structure and environmental conditions; 3) uncover the function of biocrusts in the coupled biogeochemical cycling of P- (particular emphasis!), C- and N-compounds across spatial scales from the atomic/molecular-, the single mineral grain-, biocrust patch- and soil profile- up to the slope/catchment-scale, the latter with the help of remotely sensed spectral data and jointly developed transfer functions; 4) understand how microclimatic conditions and water availability determine the biocrust community structure and activity, coverage and their functioning in the arid ecosystems. The research will start with a joint field campaign for pedological, geobotanical and physical-geographical site descriptions, observation plot instrumentation, and biocrust and soil samplings. The advanced methodological approaches involve the latest molecular-biological, electron-microscopic, plant physiological, chemical-analytical (mass- and synchrotron-based spectroscopies) and remote sensing techniques, and the corresponding multivariate data evaluation methods. The expected results will not only disclose presently unknown biocrust organisms and their physiological and ecological functioning but also enlighten their contribution to bioweathering and fundamental Earth-shaping processes, and provide overall knowledge and data background for regional or global-scale geosystem models.

在全球范围内，生物土壤结皮（生物结皮）形成了干旱地区地球临界区最具生产力的微生物生物量。生物结壳是由异养细菌、真菌、地衣、苔藓、蓝藻和藻类等活生物体及其副产品形成的，形成了一个由有机物质结合在一起的无机颗粒组成的表层土壤。它们可以被描述为生态系统工程师，形成水稳定的聚合表层，在初级生产、矿化、生物风化、灰尘捕获以及土壤、斜坡和整个景观的稳定方面发挥重要的多功能生态作用，从而影响各种尺度的养分和水文循环。密集的文献回顾使我们意识到，这些社区在南美洲几乎没有研究，尽管在优先计划的研究领域非常丰富。因此，这一跨学科的建议的目标是1）评估几乎未知的智利生物结壳类型的社区结构，使用现场和实验室的方法相结合，以解决相对丰富的全谱生物结壳有机体，特别是关于他们的作用，在风化和景观形成过程（谁在做什么？）; 2)揭示了丰富的生物体中哪些生物化学过程对生物风化有贡献，并量化了与群落结构和环境条件有关的反应速率; 3）揭示了生物结壳在P-（特别强调！）的耦合地球化学循环中的功能，C-和N-化合物的空间尺度从原子/分子-，单一的矿物颗粒-，生物结壳补丁-和土壤剖面-到斜坡/集水区规模，后者的帮助下，遥感光谱数据和共同开发的转换功能; 4）了解小气候条件和水的可用性如何决定生物结壳群落结构和活动，覆盖面及其功能在干旱生态系统。这项研究将首先进行土壤学、地植物学和自然地理地点描述、观测地块仪器以及生物结壳和土壤取样的联合实地活动。先进的方法包括最新的分子生物学、电子显微镜、植物生理学、化学分析（质谱和同步辐射光谱学）和遥感技术，以及相应的多元数据评价方法。预期结果不仅将揭示目前未知的生物结壳生物及其生理和生态功能，而且还将启发它们对生物风化和基本地球塑造过程的贡献，并为区域或全球尺度的地理系统模型提供全面的知识和数据背景。