Hydrogen Cycling and Its Relationship to Carbon Remineralization in Anoxic Marine Environments

缺氧海洋环境中的氢循环及其与碳再矿化的关系

• 批准号: 8719049
• 负责人: Mary Scranton
• 金额: $ 6.52万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-12-01 至 1989-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8719049&HistoricalAwards=false
• 关键词: Hydrogen; Cycling; Its; Relationship; Carbon

Hydrogen is a Key intermediate in the anaerobic diagenesis of organic carbon. Hydrogen partial pressures are important in controlling fermentation pathways, and theoretical arguments suggest hydrogen production rates are high. In addition, competition for hydrogen can be instrumental in determining the relative importance of sulfate reduction and methanogenesis (and possibly iron reduction) in sediments. H2 is also an important precursor for methane in methanogenic sediments (both freshwater and marine). However, relatively few data are available which permit detailed discussion of the relationship between hy>rogen geochemistry and carbon diagenesis in natural environments. Scranton has studied the distribution and cycling of hydrogen and acetate in anaerobic sediments for several years and has found that hydrogen turnover in these systems is very rapid. Production and consumption rates appear to be virtually identical (no net release or uptake of hydrogen) and appear to be closely coupled spatially (occurring in "clusters") in the sediments. Measured rates of "apparent" hydrogen production, however, are much lower than would have been predicted from acetate production rates measured simultaneously, suggesting that artifacts may remain in the measurements of production rates. Scranton proposes to estimate in situ hydrogen production rates using a new approach with very thin layers of sediment, to determine the relationship between a number of fatty acids and hydrogen concentrations in the sediments, and to extend our data set to include the relatively simpler methanogenic systems.

氢是有机碳厌氧成岩作用的关键中间体。氢分压在控制发酵途径中是重要的，理论论证表明氢的产率很高。此外，对氢的竞争可能有助于确定沉积物中硫酸盐还原和甲烷生成（可能还有铁还原）的相对重要性。氢气也是产甲烷沉积物（淡水和海洋）中甲烷的重要前体。然而，可以详细讨论自然环境中碳元素地球化学与碳成岩作用关系的资料相对较少。斯克兰顿多年来一直在研究厌氧沉积物中氢和醋酸盐的分布和循环，并发现氢在这些系统中的周转非常迅速。生产和消耗速率似乎几乎相同（没有氢的净释放或吸收），并且在沉积物中似乎在空间上紧密耦合（以“簇”形式发生）。然而，测量到的“表观”产氢率比同时测量到的醋酸酯产氢率所预测的要低得多，这表明人工制品可能存在于产氢率的测量中。斯克兰顿建议使用一种新的方法来估算非常薄的沉积物层的原位产氢率，以确定沉积物中许多脂肪酸和氢浓度之间的关系，并扩展我们的数据集，以包括相对简单的产甲烷系统。