Evaluation and quantification of microbial degradation of allochthonous organic matter by "priming" (MicroPrime)

通过“引发”对异地有机物的微生物降解进行评估和定量（MicroPrime）

基本信息

批准号：
256575941
负责人：
Professor Dr. Hans-Peter Grossart
金额：
--
依托单位：
Abteilung 3: Plankton- und mikrobielle Ökologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/256575941?language=en
关键词：
Evaluation quantification microbial degradation allochthonous

项目摘要

The main goal of this project is to characterize future changes in aquatic C-cycling via microbial mechanisms, in particular by focusing on priming effects, which have been little studied in aquatic ecosystems. Depending on environmental conditions, priming can either stimulate or inhibit microbial C-cycling. Therefore, we aim to unravel future changes in the role of priming via compound specific stable isotope analysis (e.g. 13C/12C ratio in microbial phospholipid fatty acids (PLFA)) both in field and laboratory experiments. We intend to developing suitable protocols to combine PLFA analyses with molecular methods, e.g. stable isotope probing (DNA-SIP; RNA-SIP), in particular for bacteria and fungi. This study aims to determine the impact of terrigenous OC input on priming effects, and hence on the aquatic-terrestrial coupling as well as their role for C-cycling in aquatic systems affected by global change. To our knowledge, this will be the first study testing for the metabolic transfer of 13C-labled OC from both, labile and recalcitrant OC-pools in one approach and hence investigating the underlying mechanisms of priming effects in aquatic ecosystems. Both C-pools will be supplied with different pulsing-regimes and nutrient-conditions to unravel effects of labile-OM-availability on recalcitrant organic matter (OM) degradation processes. In the first phase, laboratory experiments consisting of defined microorganisms with well characterized abilities to degrade defined substrates will be carried out and thus enable studies on basic mechanisms, interactions between organisms and their role for OM degradation. Special emphasis will be set on the role of fungi in aquatic mineralization processes. We first want to elucidate basic mechanisms concerning priming, synergistic effects of bacteria and fungi in these processes and quantify which parts of the OM-pool (labile vs. recalcitrant) are respired or incorporated into microbial biomass. In a second phase, the role of characterized basic mechanisms and organism-interactions for OM cycling will be studied using natural communities, different time courses of C-additions (pulsing to simulate more frequent inputs of C in aquatic systems) and different nutrient conditions in the medium (elemental stoichiometry). Later in a third phase, these studies will be extended to much more complex environmental conditions by using mesocosm-experiments (http://www.lake-lab.de/). Here we mainly want to challenge our gained knowledge from phase one and two under environmental conditions, in particular addressing particle fluxes under natural conditions. Our modular approach will enable us to elucidate the role of priming in C-cycling in the water column as well as at aquatic-terrestrial interfaces and hence to improve C-budgets in aquatic systems.

该项目的主要目的是通过微生物机制来表征水生C-Cycling的未来变化，特别是通过专注于启动效应，而启动效应在水生生态系统中很少研究。根据环境条件的不同，启动可以刺激或抑制微生物C-Cycling。因此，我们的目标是通过复合特异性稳定同位素分析（例如，在野外和实验室实验中微生物磷脂脂肪酸（PLFA）中的13c/12c比）来揭示启动作用的未来变化。我们打算开发合适的方案，以将PLFA分析与分子方法相结合，例如稳定的同位素探测（DNA-SIP； RNA-SIP），特别是细菌和真菌。这项研究旨在确定陆源OC输入对启动效应的影响，从而确定对水生物偶联的启动效应的影响，以及它们在受全球变化影响的水生系统中C-Cycling的作用。据我们所知，这将是一种研究13C持续OC从一种方法中从不稳定和顽固的OC池的代谢转移的研究测试，因此研究了水生生态系统中启动效应的潜在机制。两种C池都将提供不同的脉动测量和营养条件，以解散不稳定的效果对顽固的有机物（OM）降解过程的影响。在第一阶段，将进行由定义的微生物组成的实验室实验，具有良好的特征能力降解定义的底物，从而实现对基本机制，生物体之间的相互作用及其对OM降解的作用之间的研究。特殊重点将放在真菌在水生矿化过程中的作用。我们首先希望阐明有关启动，细菌和真菌在这些过程中的协同作用的基本机制，并量化OM池的哪些部分（不稳定vs. recalcitrant）被呼吸或掺入微生物生物量中。在第二阶段中，将使用自然社区，不同的c循环时间（脉冲以模拟水生系统中C中的脉冲输入更频繁）和不同的营养条件（元素固定仪）（元素史长）来研究OM循环的特征作用。在第三阶段的后期，这些研究将扩展到更复杂的环境条件，并使用中cosm-示例（http://www.lake-lab.de/）。在这里，我们主要希望在环境条件下从第一阶段和第二阶段挑战我们获得的知识，特别是在自然条件下解决粒子通量。我们的模块化方法将使我们能够阐明启动在水柱中以及在水生间接口中的C循环中的作用，从而改善水生系统中的C预算。