Collaborative Research: Are Carbon Fluxes from Marine Sediments Enhanced by Submarine Ground Water Discharge?

合作研究：海底地下水排放是否增强了海洋沉积物中的碳通量？

• 批准号: 0403842
• 负责人: Jennifer Cherrier
• 金额: --
• 依托单位: Florida Agricultural and Mechanical University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0403842&HistoricalAwards=false
• 关键词: Collaborative; Research; Carbon; Fluxes; Marine

0403842CherrierThe flux of C from coastal marine sediments is likely to be influenced by submarine ground water discharge (SGD), which may enhance remineralization of buried C and transport it to the water column. Previous studies reveal that SGD includes both meteoric water from continental aquifers and surface water mixed into shallow sediment through processes such as wave and tidal pumping, density driven flow, and bioirrigation. Surface water is saturated with oxygen, and thus should remineralize organic carbon that otherwise would be sequestered in the sediments. The process of mixing and enhanced remineralization will be studied in the Indian River Lagoon System (eastern Florida), where changes in water column salinity and pore waters have been used previously, and will be used in this study, to trace pumping of oxygenated surface water into the sediments. The study will use time-series measurements and monitoring of conservative tracers (conductivity, Cl- concentration, 222Rn activity, and temperature) to determine the temporal and spatial scales of mixing, as well as variations through time and space of discharge from the regional aquifers. Combining Cl- and conductivity allows greater temporal and spatial resolution than either one alone. Simultaneous measurements of Cl- concentration, conductivity, and 222Rn activity provide unique information because of their distinct compositions in end-member water sources. The hydrologic studies will be coupled with studies of remineralization of C in the sediments using C concentrations and 13C and 14C as tracers of the sources of C. Carbon in the mixed zone will be depleted in 14C because detrital organic carbon will be up to several thousand years old depending on depth of burial. Carbon in the meteoric water will be even more depleted in 14C depending on the flow paths and rates. The d13C values will be controlled by the source of C from carbonate or organic matter and provides a powerful complement to the 14C measurements. Results of the study should provide information on the efficiencies of C transformation, spatial and temporal variations of hydrologic controls on those transformations and fluxes in coastal sediments, and information on C cycling in marine sediments from hydrologic processes, an important first step toward quantitative estimates of sources to the global C cycle. The study will also develop new isotopic tracing techniques to study these processes. The study has important management implications for the local study site, which is in the National Estuaries Program, is one of the most biologically diverse estuaries in the nation, and home to 21 endangered or threatened species. The project impacts the educational missions of the University of Florida (a Research I institution), Florida A&M University (a Historically Black and Minority Serving College/University), and Louisiana State University (located in an EPSCoR state) through involvement of high school to graduate students, both through course work that will be linked to the Florida Center for Ocean Science Education Excellence (FCOSEE) web portal, and directly in the project, which offers a broad range of learning opportunities (hydrology and biogeochemistry).

0403842CHERRIER THERTHE COSTAL海洋沉积物的C通量可能会受到海底地下水排放（SGD）的影响，这可能会增强埋藏的C并将其运输到水柱上。 先前的研究表明，SGD包括大陆含水层的陨石水和地表水通过波浪和潮气泵，密度驱动的流动和生物灌溉的过程混合到浅层沉积物中。 地表水用氧气饱和，因此应回忆起有机碳，否则将在沉积物中隔离。 将在印度河泻湖系统（佛罗里达州东部）中研究混合和增强的回忆性过程，在该系统中，以前已经使用了水柱盐度和孔隙水的变化，并将在这项研究中用于追踪将含氧的地表水泵入沉积物中。 该研究将使用时间序列测量和监测保守的示踪剂（电导率，CL浓度，222RN活性和温度）来确定混合的时间和空间尺度，以及通过区域含水层排出的时间和空间的变化。 将CL和电导率组合起来可以比单独使用任何一个更大的时间和空间分辨率。 同时测量Cl浓度，电导率和222RN活性，因为它们在末端成员的水源中具有独特的组成，提供了独特的信息。 水文研究将与使用C浓度和13C和14C在混合区中的C.碳来源的示踪物中对C在沉积物中C的研究结合使用，因为碎屑有机碳将根据埋葬深度的数千年。 根据流动路径和速率，陨石中的碳将在14C中更加耗尽。 D13C值将由碳酸盐或有机物的C来源控制，并为14C测量提供了强大的补充。 该研究的结果应提供有关C转化的效率，水文控制的空间和时间变化的信息，这些变化对沿海沉积物中这些转化和通量的效率，以及从水文过程中C Cycligents中C循环的信息，这是朝着全球C周期定量估算的重要的第一步。 该研究还将开发新的同位素追踪技术来研究这些过程。 这项研究对国家河口计划中的当地研究地点具有重要的管理意义，它是该国生物学上最多样化的河口之一，并且是21种濒临灭绝或受到威胁的物种。 该项目影响佛罗里达大学（一项研究机构），佛罗里达州A＆M大学（历史上是黑人和少数派服务学院/大学）和路易斯安那州立大学（位于EPSCOR州立大学），通过参与研究生，通过课程，将在弗洛里达的范围内链接到Florida Exparione Opport of Forporce，并直接链接到Portal的Portal，并将（水文和生物地球化学）。