Temporal and spatial dynamics of organic carbon in intermittent springs – Environmental drivers and connectivity to headwater streams

间歇泉水中有机碳的时空动态 â 环境驱动因素和与源头河流的连通性

• 批准号: 461420208
• 负责人: Professor Dr. Peter Chifflard
• 金额: --
• 依托单位: Institut für Geographie und Regionalforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/461420208?language=en
• 关键词: Temporal; spatial; dynamics; organic; carbon

Springs are the birth of headwater streams. They represent the starting point of the river continuum, and are important ecotones between groundwater and surface water. Intermittent springs originate from near-surface, unconfined aquifers. They display a temporarily groundwater disconnected flow regime, short residence times and may act as sources of organic carbon (OC) to headwater streams. As a result, intermittent springs have the potential to significantly impact carbon fluxes in headwater streams. However, only a few eco-hydrological studies have addressed springs as distinct sources of OC, and it is still unclear how the variable flow regime impacts the temporal variability or organic carbon in these diverse ecotones, which are typical for low mountain ranges. Therefore, the objective of this proposal is to investigate the spatial and temporal dynamics of OC in intermittent springs, environmental drivers of these processes, and their downstream impact in different low mountain ranges. Systematically investigating 44 intermittent springs in different low mountain ranges (Rhenish Slate Mountains, Ore Mountains, Black Forest), we will use hydrological and biogeochemical data to further elucidate OC dynamics at different temporal and spatial scales. In addition to the permanent monitoring of spring discharge, electrical conductivity and water temperature; seasonal and event-based measurements of OC, nutrients and stable isotopes will be carried out. Using an array of state-of-the-art laboratory equipment and methods (C/N- and TOC-Analyzer, Picarro), we will analyse the temporal and spatial variability of DOC, POC, optical properties (fluorescence, absorbance), nutrients (PO4, NO3, NO2, NH4) and stable isotopes (18O, 2H). We will employ a range of multivariate statistical techniques (e.g., PCA, CCA), to identify spatial and temporal patterns, processes and drivers. We will model the sources and fluxes of spring OC (PARAFAC, SIMMR mixing model, LOADest, machine learning). This cross-scale study of the hydrological and biogeochemical properties of intermittent spring and their spatial and temporal dynamics will close the existing knowledge gap regarding the role of intermittent springs within the river continuum concept. This would further contribute to the understanding of potential shifts in the dynamics of springs due to climate change induced variations in precipitation and runoff, and the impact of their changes on both the spring ecosystem, as well as related headwater streams.

泉是源头活水的源泉。它们是河流连续体的起点，是地下水和地表水之间的重要交错带。间歇泉来自近地表的无压含水层。他们显示一个临时的地下水断开流态，停留时间短，并可能作为有机碳（OC）的源头流。因此，间歇性泉水有可能显著影响源头河流中的碳通量。然而，只有少数生态水文学研究已经解决了泉水作为OC的不同来源，目前还不清楚可变的流量制度如何影响这些不同的生态交错区，这是典型的低山脉的时间变异性或有机碳。因此，本提案的目的是调查OC的空间和时间动态的间歇泉，这些过程的环境驱动因素，以及它们在不同的低山脉的下游影响。通过对不同低山地区（莱茵板岩山、矿石山、黑森林）44个间歇泉的系统调查，利用水文和地球化学资料，进一步阐明不同时空尺度上OC的动态。除了对泉水流量、电导率和水温进行长期监测外，还将对OC、营养物质和稳定同位素进行季节性和基于事件的测量。使用一系列最先进的实验室设备和方法（C/N和TOC分析仪，Picarro），我们将分析DOC，POC，光学特性（荧光，吸光度），营养物质（PO 4，NO3，NO2，NH 4）和稳定同位素（18 O，2 H）的时间和空间变异性。我们将采用一系列多变量统计技术（例如，（a）通过分析和评价（PCA、CCA），确定空间和时间模式、进程和驱动因素。我们将模拟春季OC的来源和通量（PARAFAC，SIMMR混合模型，LOADest，机器学习）。这种跨尺度的水文和间歇性泉及其时空动态的地球化学性质的研究将关闭现有的知识差距间歇性泉的作用在河流连续体的概念。这将进一步有助于了解由于气候变化引起的降水和径流变化，以及它们的变化对春季生态系统以及相关的源头河流的影响，导致的泉水动态的潜在变化。