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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.

该项目的主要目标是通过微生物机制表征未来水生碳循环的变化，特别是通过关注引发效应，这在水生生态系统中很少研究。根据环境条件，预充可以刺激或抑制微生物C循环。因此，我们的目标是通过化合物特异性稳定同位素分析（例如微生物磷脂脂肪酸（PLFA）中的13 C/12 C比率），在现场和实验室实验中揭示引发作用的未来变化。我们打算开发合适的协议，结合联合收割机PLFA分析与分子方法，如稳定同位素探测（DNA-SIP; RNA-SIP），特别是对细菌和真菌。本研究旨在确定陆源有机碳输入的启动效应的影响，从而对水-陆耦合以及它们的作用，在受全球变化影响的水生系统中的C-循环。据我们所知，这将是第一个研究测试的13 C-标记的OC从两个，不稳定的OC池中的一种方法的代谢转移，从而调查在水生生态系统中的启动效应的潜在机制。这两个C池将提供不同的脉冲制度和营养条件，以解开不稳定的有机质（OM）的降解过程中的有效性的影响。在第一阶段，将进行实验室实验，包括确定的微生物具有良好的表征能力，降解确定的底物，从而使基本机制，生物体之间的相互作用及其作用的OM降解的研究。将特别强调真菌在水生矿化过程中的作用。我们首先要阐明有关启动，在这些过程中的细菌和真菌的协同效应的基本机制，并量化OM池（不稳定与不稳定）的哪些部分被呼吸或纳入微生物生物量。在第二阶段，特征的基本机制和有机体的相互作用OM循环的作用将使用自然社区，不同的时间进程的C-添加（脉冲模拟更频繁的输入C在水生系统）和不同的营养条件下的介质（元素化学计量）进行研究。在第三阶段的后期，这些研究将通过使用中宇宙实验扩展到更为复杂的环境条件（http：//www.lake-lab.de/）。在这里，我们主要想挑战我们从第一阶段和第二阶段在环境条件下获得的知识，特别是解决自然条件下的颗粒通量。我们的模块化的方法将使我们能够阐明的作用，启动C-循环中的水柱，以及在水生-陆地界面，从而提高C-预算在水生系统。