OFFshore freshened groundwater systems – Emergence and persistence analysis by geochemical modellING (OFFING)

近海淡水地下水系统 â 通过地球化学建模进行出现和持久性分析 (OFFING)

• 批准号: 507217178
• 负责人: Dr. Christian Hensen
• 金额: --
• 依托单位: GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/507217178?language=en
• 关键词: OFFshore; freshened; groundwater; systems; Emergence

Offshore freshened groundwater (OFG) is a ubiquitous phenomenon in continental margins worldwide. The identification of OFG occurrences and the prediction of their volumes gained increasing attention over the past two decades due to implications for water resources, ecosystem function and global element budgets. However, in spite of recent scientific progress, our knowledge of emplacement mechanisms and the evolution of fresh groundwater in the offshore environment still remains sketchy. In many cases, it is not known if OFG bodies are actively recharged at present or are rather remnants of past environmental conditions. The proposed study will address this knowledge gap by applying innovative 1D and 2D numerical transport-reaction models to geochemical data from IODP drilling efforts at two continental margins, offshore New Zealand (Leg 317) and New Jersey (Leg 313). To date, our perception of OFG flow patterns in these areas and their development over time are essentially derived from large-scale hydrogeological models. These, however, do not sufficiently reproduce (due to insufficient spatial resolution) or are even in conflict with available geochemical data from IODP drilling. In this proposal, we suggest conducting an unprecedented, quantitative evaluation of pore water geochemical data from several drill cores in order to constrain and evaluate emplacement mechanisms and timing of OFG at Legs 313 and 317. Our findings may have important implications for sustainable exploitation of OFG as a source of potable water in coastal cities and its role in global element cycles.

海洋淡水是全球大陆边缘地区普遍存在的现象。由于对水资源、生态系统功能和全球元素预算的影响，在过去的二十年中，OFG分布的确定和其量的预测越来越受到关注。然而，尽管最近的科学进步，我们的知识的安置机制和淡水地下水的演变在近海环境仍然是粗略的。在许多情况下，我们不知道OFG体目前是主动充电，还是过去环境条件的残余。拟议的研究将通过将创新的1D和2D数值传输-反应模型应用于来自两个大陆边缘，新西兰近海（Leg 317）和新泽西州（Leg 313）的IODP钻井的地球化学数据来解决这一知识差距。迄今为止，我们对这些地区的OFG流动模式及其随时间发展的看法基本上来自大规模水文地质模型。然而，这些数据不能充分再现（由于空间分辨率不足），甚至与来自IODP钻探的现有地球化学数据相冲突。在该提案中，我们建议对几个岩心的孔隙水地球化学数据进行前所未有的定量评估，以约束和评估313和317段OFG的就位机制和时间。我们的研究结果可能对沿海城市饮用水OFG的可持续开发及其在全球元素循环中的作用具有重要意义。