Organic matter: Abiotic transformations and microbial interactions

DynaDeep将揭示高能海滩下海洋-陆地相互作用的功能和相关性，在那里，我们建议深层地下作为一个动态的生物反应器和独特的微生物栖息地，影响元素净通量到海洋。为实现这一目标，六个分项目将在联合实地活动、共享取样方法以及实验工作方面进行合作，并以综合方法使用数学模型。分项目P3将研究有机物的来源、组成和转化，作为深层地下河口海洋地球化学过程的主要驱动力。我们假设，深层地下的瞬态特性是至关重要的营业额和有机物质的分子转化，通过相互作用的非生物和生物过程。有针对性的实验室实验和现场工作相结合，以确定和表征（1）潜在的有机质供应到地下河口，（2）非生物变化的溶解有机质（DOM）的数量和组成发生在时间和空间可变的氧化还原界面，和（3）降解和转化DOM的微生物群落。详细的分子信息将用于破译DOM和微生物群落组成和活动之间的联系。将采用最先进的分子方法，如高分辨率傅里叶变换离子回旋共振质谱法和超高效液相色谱法，并辅之以稳定同位素和放射性碳同位素的分析，来确定有机物质的组成。将建立分子代用指标，作为深层地下特定生物地球化学状态和由此产生的微生物生态位空间的诊断工具。来自P3的结果将填充耦合反应传输水文地质模型（P6）与反应性条款，并提供有关DOM（P1）的来源和年龄的信息。在P3中获得的分子数据将在微生物群落数据（P5）和关键微量元素（P4）分布的背景下进行解释，并将有助于对微生物呼吸（P2）的机理理解。

DynaDeep will unravel the functionality and relevance of marine-terrestrial interactions below high-energy beaches, where we propose the deep subsurface to act as a dynamic bioreactor and unique microbial habitat affecting elemental net fluxes to the sea. To reach this goal, six subprojects will cooperate in joint field campaigns, shared sampling approaches as well as experimental work and use mathematical models in an integrative approach. Subproject P3 will study the sources, composition and transformations of organic matter as the main drivers of biogeochemical processes in the deep subterranean estuary. We hypothesize that the transient character of the deep subsurface is crucial for the turnover and molecular transformation of organic matter through interacting abiotic and biotic processes. A combination of targeted laboratory experiments and field work will be applied in order to identify and characterize (1) potential endmembers of organic matter supplied to the deep subterranean estuary, (2) abiotic changes of dissolved organic matter (DOM) quantity and composition occurring at temporally and spatially variable redox interfaces, and (3) degradation and transformation of DOM by microbial communities. Detailed molecular information will be used to decipher linkages between DOM and microbial community composition and activity. Organic matter composition will be characterized by state-of-the-art molecular approaches such as ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and ultra-performance liquid chromatography, and complemented by analyses of stable and radiocarbon isotopes. Molecular proxies will be established as diagnostic tools for specific biogeochemical states of the deep subsurface and the resulting microbial niche space. Results from P3 will populate the coupled reactive transport hydrogeological model (P6) with reactivity terms and provide information on sources and age of DOM (P1). Molecular data acquired in P3 will be interpreted in the context of microbial community data (P5) and distribution of key trace elements (P4), and will contribute to a mechanistic understanding of microbial respiration (P2).