Modular system for measuring carbon and nitrogen concentrations and isotopes

为了在不同时空尺度上开展与土地利用和气候变化影响相关的开创性研究，需要一个用于测量土壤、沉积物、有机样品和水中碳（C）和氮（N）的IRMS系统。由于采用模块化设计，元素分析中的新系统可以测量 C 和 N 浓度以及相应的稳定同位素。 (1) 土壤和沉积物中的 C 和 N 浓度是有机物存在的指标。这可以提供有关农业造成的土壤退化、表土侵蚀、有机物质是否已被冲入湖泊沉积物或聚居区有机残留物等信息，这些残留物可以表明人类活动。了解 C 含量也是进一步分析的基础，例如生物标志物分析。 (2) 在地质考古学和考古植物学中，植物残留物中稳定氮同位素的测量表明有机（绿肥或粪肥）肥料的使用，因为当地氮同位素比率更受土壤管理而不是气候的影响。拟议的跨学科项目可以弥补正在出现的重大研究空白。在古生态学中，稳定碳和氮同位素的测量对于深入了解气候和植被历史非常重要。应用示例是分析生态系统中 C3 和 C4 植物的比例与干旱度的关系，这与稀树草原和草原的地质考古和生态研究相关，其中植物的同位素变化也反映在土壤和放牧动物中。新作物（例如小米）的引入也可以使用 C 同位素在考古发现中得到证明。 (3) 对于土壤侵蚀动力学的研究，从土壤中冲走并溶解在水中的有机物的定量和定性非常重要。通过农业用地的土壤侵蚀，有机物输入到湖泊中，会导致湖泊沉积物的 δ15N 和 δ13C 值发生变化，这在史前时期也是可以测量的。在这方面，我们对潜在过程的理解以及解释沉积物中同位素数据的可能性仍然存在差距。这些系统的使用并不是地质考古学中的标准应用。因此，C 和 N 同位素的现场测量是开发方法和解决新研究问题的重要先决条件，这也是将我们定位为国际生态地质考古研究中心的独特机会。一个独特的附加功能是测量土壤水中同位素的模块。

In order to conduct pioneering research related to the effects of land use and climate change on different temporal and spatial scales, an IRMS system for measuring carbon (C) and nitrogen (N) in soils, sediments, organic samples and water is required. Thanks to their modular design, new systems in element analysis allow both the measurement of C and N concentrations and the measurement of the respective stable isotopes. (1) C and N concentrations in soils and sediments are indicators for the presence of organic matter. This can provide information on, e.g., soil degradation due to agriculture, eroded topsoil material, if organic material has been washed into lake sediments, or organic residues in a settlement area that can indicate anthropogenic activities. Knowledge of the C content is also the base for further analysis, e.g. biomarker analysis. (2) In geoarchaeology and archaeobotany, the measurement of stable N-isotopes in plant residues indicates the use of organic (green or manure) fertilizer, since locally N-isotope ratios are rather influenced by soil management than by climate. Occurring major research gaps could be closed by the proposed interdisciplinary projects. In paleoecology, the measurement of stable C and N isotopes is important to gain insight into the climate and vegetation history. Examples of applications are the analyses of the proportion of C3 and C4 plants in an ecosystem as a function of aridity, which is relevant for geoarchaeological and ecological studies in savannas and steppes, where isotopic changes in plants are also reflected in soils and grazing animals. The introduction of new crops (e.g. millet) can also be demonstrated in archaeological findings using C isotopy. (3) For the study of soil erosion dynamics, the quantification and qualification of the organic matter that is washed out of the soil and dissolved in the water is important. The input of organic matter into lakes through soil erosion from agricultural land can lead to changes in δ15N and δ13C values of lake sediments, which was also measurable for prehistoric periods. Here, too, are still gaps in our understanding of the underlying processes and the possibility of interpreting the isotope data in sediments. The use of these systems is not a standard application in geoarchaeology. The on-site measurement of the C and N isotope is therefore an important prerequisite for developing methods and working on new research questions, and it would be a unique opportunity to position ourselves internationally as a center for ecological-geoarchaeological research. A unique addition would be the module for measuring the isotopes in soil water.