Organic matter oxidation and aragonite diagenesis in a coral reef
Organic matter oxidation and aragonite diagenesis in a coral reef
复制标题
珊瑚礁中的有机物氧化和文石成岩作用
DOI：
--
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
G. Tribble
中科院分区：
文献类型：
--
作者：
G. Tribble
摘要采用野外工作和理论工作相结合的方法，研究珊瑚礁框架内文石饱和状态的控制。采用封闭体系离子形态模型评价了有机质氧化对文石饱和度的影响。文石的饱和状态最初降至1以下，但在硫酸盐还原过程中变得过饱和。有机质的C/N比影响过饱和程度，贫氮有机物质导致体系对文石的腐蚀性更强。硫化亚铁的析出强烈影响文石的饱和状态，形成较多FeS的体系相对于文石有更强的过饱和倾向。如果模型体系保持文石饱和，则在有机反应途径的不同阶段预测文石的析出和溶解。来自珊瑚礁框架的现场数据表明，该系统保持在文石饱和状态，模型预测的溶解钙变化遵循在珊瑚礁间隙水域观察到的变化。文石可能在调节间隙水的pH中起到固相缓冲的作用。由于珊瑚礁中的间隙水停留时间很短，观察到的平衡表明动力学很快。
ABSTRACT A combination of field and theoretical work is used to study controls on the saturation state of aragonite inside a coral-reef framework. A closed-system ion-speciation model is used to evaluate the effect of organic-matter oxidation on the saturation state of aragonite. The aragonite saturation state initially drops below 1 but becomes oversaturated during sulfate reduction. The C:N ratio of the organic matter affects the degree of oversaturation, with N-poor organic material resulting in a system more corrosive to aragonite. Precipitation of sulfide as FeS strongly affects the aragonite saturation state, and systems with much FeS formation will have a stronger tendency to become oversaturated with respect to aragonite. Both precipitation and dissolution of aragonite are predicted at different stages of the organic reaction pathway if the model system is maintained at aragonite saturation. Field data from a coral-reef framework indicate that the system maintains itself at aragonite saturation, and model-predicted changes in dissolved calcium follow those observed in the interstitial waters of the reef. Aragonite probably acts as a solid-phase buffer in regulating the pH of interstitial waters. Because interstitial water in the reef has a short residence time, the observed equilibration suggests rapid kinetics.