Measurement of Oxygen Uptake from Marine Sediments by Eddy Correlation

通过涡相关测量海洋沉积物的摄氧量

• 批准号: 0221259
• 负责人: Peter Berg
• 金额: $ 22.88万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0221259&HistoricalAwards=false
• 关键词: Measurement; Oxygen; Uptake; Marine; Sediments

ABSTRACTOCE-0221259Oxygen transport into sediments in natural marine environments is mediated by the turbulent transport scales of motion of the bulk overlying solution, molecular diffusion being orders of magnitude slower and a virtually insignificant term. The oxygen consumption by sediments, conventionally quantified by either laboratory measurements on recovered cores or by the artifice of an in-situ enclosure experiment, is a key parameter in assessing organic matter decomposition rates and also controls the oxidation of sediment reductants such as NH4+, Mn2+, Fe2+, HS-, FeS etc produced during anaerobic respiration. Ventilation and irrigation of sedimentary layers either by wave induced pumping or bioturbation activity are also processes that could potentially be quantified by more reliable measurements of sediment O2 uptake.This proposal will extend and explore a recently suggested approach being jointly developed by the PI together with colleagues at the Max Planck Institute for Marine Microbiology (Bremen). The technique involves correlating the time varying concentration of dissolved oxygen, measured by fast response microelectrodes, in the sediment boundary layer within a few cm of that surface with locally sensed vertical velocity components also sampled at high frequency by acoustic Doppler velocimetry (ADV). An eddy correlation approach has direct analogues with similar techniques that are used by atmospheric scientists measuring scalar (e.g. heat, moisture (momentum) and trace gas) fluxes in the planetary boundary layer. Theoretical and practical considerations for the adaptation of the basic approach into aquatic systems are discussed and will be explored at shallow coastal field sites in Denmark (Aarhus Bay).

ABSTRACTOCE-0221259在自然海洋环境中，氧气输送到沉积物中是由上覆溶液的湍流输送运动尺度介导的，分子扩散速度要慢几个数量级，而且实际上是一个微不足道的术语。沉积物的耗氧量通常通过对回收的岩心进行实验室测量或通过原位封闭实验的方法进行量化，是评估有机物分解速率的关键参数，并且还控制沉积物还原剂（例如 NH4+、Mn2+）的氧化无氧呼吸时产生的Fe2+、HS-、FeS等。通过波浪引起的抽水或生物扰动活动对沉积层进行通风和灌溉也是可以通过更可靠的沉积物 O2 吸收测量来量化的过程。该提案将扩展和探索最近由 PI 与同事共同开发的建议方法马克斯·普朗克海洋微生物学研究所（不来梅）。该技术涉及将距离表面几厘米内的沉积物边界层中的溶解氧浓度（通过快速响应微电极测量）与局部感测的垂直速度分量（也通过声多普勒测速法（ADV）以高频采样）相关联。涡相关方法与大气科学家测量行星边界层中的标量（例如热量、水分（动量）和痕量气体）通量的类似技术有直接的相似之处。讨论了将基本方法应用于水生系统的理论和实践考虑，并将在丹麦（奥胡斯湾）的浅海沿海现场进行探索。