Development of an In Situ Pore Water Sampler for Scientific Ocean Drilling

沉积物孔隙水是存在于沉积物颗粒之间的水域，是通过科学海洋钻探获得许多重大发现的基础。然而，50年前用于提取孔隙水的相同技术今天仍然存在，尽管存在已知的采样文物。拟议的项目将开发、测试和交付一种新型的流体取样器，该取样器将为一系列化学、微生物和溶解气体分析提供原始的就地孔隙水。新型取样器将使用惰性材料来保存原始流体，考虑到将人工制品降至最低的取样程序，并可在科学钻探船上的标准程序范围内操作。此外，采样器还将提供新的功能，适用于进行操纵性实验，例如评估微生物代谢率和功能以及收集沙质沉积物中的流体。这一新的能力是所需的创新之一，它将提供新的数据类型，以描述和了解深海沉积物中广泛的跨学科联系过程。阐明这些过程将有助于实现2050年科学框架中概述的目标和目的，该文件由一个国际海底科学钻探科学家联盟开发，受到国家科学基金会的好评。拟议中的原位流体采样器将利用先进活塞取样器(APC)切割鞋内的小空间，这是回收浅层(数百米)沉积物的标准工具。在将APC注入沉积物后的15分钟内，拟议的采样器将能够收集多达52毫升的液体。为了达到这样的流体收集率，我们将在实验室环境中测试取样器的各种组件(剪切销、扳机弹簧、活塞弹簧和熔块)的沉积物成分和孔隙度。这些测试的结果将指导为期7天(运输1天)的取心作业，以评估性能，并将化学结果与从各种天然沉积物类型的Rhizon回收的孔隙水中的化学结果进行比较。在生产用于US-IODP科学钻探计划的四个采样器之前，将进行额外的改装和/或实验室测试，从而扩大舰载科学的能力。拟议的采样器将支持一种新型的流体采集，它将提高我们对生物地球化学过程的理解(例如，消除富碳酸盐沉积物中的钙和碱度伪迹)，提供流体来测试两种不同微生物种群(自由漂浮和颗粒附着)的潜力，允许一个人在采样器中加入杀菌剂、修饰剂或浓缩溶液进行微生物研究，或收集用于溶解气体分析的流体。这些新的能力将提供实现2050年科学框架中的目标和目的所必需的新数据类型，该框架是通过海底科学钻探可以实现的科学优先事项的国际指南。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Sediment pore waters, which are waters that exist between sediment particles, serve as the foundation for many significant discoveries through scientific ocean drilling. Yet, the same technique used to extract pore waters employed 50 years ago remains today, even though known sampling artifacts exist. The proposed project will develop, test, and deliver a novel fluid sampler that will provide pristine in situ pore waters for a range of chemical, microbial, and dissolved gas analyses. The novel sampler will utilize inert materials to preserve pristine fluids, account for sampling procedures that minimize artifacts, and be operational within the context of standard procedures on a scientific drilling vessel. In addition, the sampler will also provide new functionality, suitable for conducting manipulative experiments to, for example, assess microbial metabolic rate and function and collect fluids in sandy sediment. This new capability represents one of the needed innovations that will provide new data types to characterize and understand a broad range of interdisciplinary-linked processes in deep-sea sediment. Elucidating such processes will help to achieve goals and objectives outlined in the 2050 Scientific Framework, a document that was developed by an international consortium of scientists for seafloor scientific drilling and was well received within the National Science Foundation.The proposed in situ fluid sampler will take advantage of a small space within the cutting shoe of the Advanced Piston Corer (APC), which is a standard tool for recovering shallow ( several hundred meters) sediment. The proposed sampler will be able to collect up to 52 ml of fluid within 15 minutes after the APC is injected into the sediment. To achieve this rate of fluid collection we will test various components of the sampler (shear pins, trigger spring, piston spring, and frit) in the context of sediment composition and porosity in a laboratory setting. Results from these tests will guide a 7-day (1 day of transit) coring operation to assess performance and to compare chemical results with those from Rhizon-recovered pore waters from a variety of natural sediment types. Additional modifications and/or laboratory tests will be conducted prior to the production of four samplers for use with the US-IODP scientific drilling program, thus expanding the capability of shipboard science. The proposed sampler will support a new type of fluid collection that will improve our understanding of biogeochemical processes (e.g., eliminating the Ca and alkalinity artifact in carbonate-rich sediment), provide fluids to test the potential for two different microbial populations (free-floating and grain-attached), allow one to prime the sampler with biocide, amendment, or enrichment solutions for microbial studies, or collect fluids for dissolved gas analysis. These new capabilities will provide new data types that will be necessary to achieve the goals and objectives in the 2050 Scientific Framework, an international guide to scientific priorities that can be achieved with seafloor scientific drilling.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.