Mineralization, stabilization, and re-mobilization of organic substances in microhabitats - the role of microorganisms in carbon and energy flows (MicroHabits)

土壤微生物对碳矿化和稳定的重要性日益被认识到，并通过微生物C泵的概念来描述。然而，这一框架内的潜在机制和控制到目前为止还知之甚少，过去的大多数研究只集中在C动力学的特定方面。我们计划通过将微生物C泵的概念与三个重要的微生境联系起来来填补这一空白，以了解C矿化(碎屑层)、C稳定(矿物表面)和C再动员(蚯蚓铸件)阶段的碳流。当前提议的新挑战是通过将碳和微生物动力学与能量通量和热力学原理联系起来来提高我们的概念性理解。我们将在一系列微型实验中解决这一挑战，在这些实验中，我们将跟踪13C和来自纤维素和玉米垃圾的能量流进入不同的池，结合同位素(全质量平衡，包括13C、13C PLFA、13C氨基糖、13Corg、13C-EOC)与量热(热量产生)和分子生物学(qPCR、Illumina PCR扩增序列测定、DNA-SIP)方法。对线虫的分析将证明碳和能量流向更高的营养水平。我们建议的一部分是三个互补的核心实验之一，这三个实验一起覆盖了SPP中提出的土壤、基质和边界条件的整个潜在数据空间。在这些核心实验中获得的数据将提供给整个SPP。总之，我们的项目将强调特定的微生境对土壤中C稳定的微生物作用的重要性。

The importance of soil microorganisms for carbon mineralization and stabilization is increasingly recognized and described through the concept of the microbial C pump. However, the underlying mechanisms and controls within this framework are to date poorly understood and most studies in the past have focused only on specific aspects of C dynamics. We plan to fill this gap by linking the concept of the microbial C pump to three important microhabitats to understand the carbon flow during phases of C mineralization (detritusphere), C stabilization (mineral surfaces), and C re-mobilization (earthworm casts). The new challenge for the current proposal is to improve our conceptual understanding by linking C and microbial dynamics to energy fluxes and thermodynamic principles. We will address this challenge in a series of microcosm experiments in which we will follow 13C and energy flow from cellulose and maize litter into different pools combining isotopic (full mass balances including 13Cmic, 13C PLFA,13C amino-sugars,13Corg,13C-EOC) with calorimetric (heat production) and molecular biological (qPCR, Illumina PCR amplicon sequencing, DNA-SIP) methods. Analyses of nematodes will demonstrate C and energy flow into higher trophic levels. One part of our proposal is one of three complementary core experiments, which together cover the entire potential data space of soils, substrates, and boundary conditions proposed in the SPP. The data obtained in these core experiments will be available to the whole SPP. In conclusion, our project will underline the importance of specific microhabitats for the microbial role of C stabilization in soil.