THE KINETICS OF ORGANIC-MATTER MINERALIZATION IN ANOXIC MARINE-SEDIMENTS
THE KINETICS OF ORGANIC-MATTER MINERALIZATION IN ANOXIC MARINE-SEDIMENTS
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DOI：
10.1357/002224091784995710
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发表时间：
1991-11-01
影响因子：
0.5
通讯作者：
BURDIGE, DJ
中科院分区：
文献类型：
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作者：
BURDIGE, DJ
在切萨皮克湾南部的5个地点的沉积物中，使用长期（> 200 d）的沉积物分解实验的硫酸盐还原和无机营养盐的生产（SIGMA-CO2，铵，磷酸盐）的动力学进行了研究。 这些过程的平均一级速率常数（在25 ℃）在表层沉积物（0-2厘米）中从8.2年-1降至3.7年-1，在12-14厘米处降至2.1年-1至0.2年-1。 C/N和C/P比的有机质进行分解，也增加了在这些网站的深度。 基于多G模型建立的有机质分解模型（以下简称混合物模型）可用于研究上述过程的动力学特征。 与多G模型一样，混合物模型的基础是沉积物中有机物的矿化，这些矿化来自具有不同反应性的不同有机物组分。 然而，在这里，反应性的差异是由两个内在的分解速率常数以及馏分中的有机物的C/N或C/P比的差异表示。 混合物模型是有用的解释这些实验的结果，并提供了解释在这些网站的表层沉积物中的有机物的反应性的差异。 它似乎也提供了信息的性质的有机物进行矿化在这些沉积物中，根据预测的C/N或C/P比，这些表观馏分。 还使用最近提出的米德尔堡（1989）的功效模型检查了本研究的数据。 这一分析表明，沉积前分解的重要性，在影响沉积有机物质的反应性。虽然所有这些模型提供了深入了解海洋沉积物中的有机物矿化，他们也都有混合的成功描述（在一个统一的方式）硫酸盐还原和无机营养盐生产在这些南部切萨皮克湾沉积物。 这一观察结果表明，在解释信息时必须小心（例如，速率常数、元素比率或沉积有机物的表观初始年龄）对沉积物中有机物的影响。 独立验证这些模型导出的参数的沉积有机物进行矿化的能力可能是重要的，在进一步完善这些模型，并提高其在描述（和预测）控制海洋沉积物中的有机物矿化的因素的有用性。
The kinetics of sulfate reduction and inorganic nutrient production (SIGMA-CO2, ammonium, and phosphate) were examined in the sediments at five sites in the southern Chesapeake Bay, using long term (> 200 d) sediment decomposition experiments. Average first order rate constants for these processes (at 25-degrees-C) decreased from 8.2 to 3.7 yr-1 in the surface sediments (0-2 cm), to 2.1 to 0.2 yr-1 at 12-14 cm. The C/N and C/P ratios of the organic matter undergoing decomposition also increased with depth at these sites. Taken together, these results indicate that the reactivity of the organic matter undergoing mineralization decreases with depth in these sediments.A model based on the multiple-G model for organic matter decomposition (hereafter referred to as the mixture model) was developed to examine the observed kinetics of all of these processes. As in the multiple-G model, the mixture model is based on the mineralization of organic matter in sediments occurring from distinct fractions of organic matter with differing reactivities. However here, differences in reactivity are indicated by differences in both the intrinsic rate constants for decomposition as well as the C/N or C/P ratios of the organic matter in the fractions. The mixture model was useful in interpreting the results of these experiments, and provided explanations for differences in the reactivity of organic matter in the surface sediments at these sites. It also appeared to provide information on the nature of the organic matter undergoing remineralization in these sediments, based on the predicted C/N or C/P ratios of these apparent fractions. The data from this study was also examined using the recently presented power model of Middelburg (1989). This analysis indicated the importance of pre-depositional decomposition in affecting the reactivity of sedimentary organic matter.While all of these models provided insights into organic matter remineralization in marine sediments, they also all had mixed successes in describing (in a unified fashion) sulfate reduction and inorganic nutrient production in these southern Chesapeake Bay sediments. This observation indicates that care must be taken in interpreting information (e.g., rate constants, elemental ratios or apparent initial ages of the sedimentary organic matter) on organic matter in sediments, based on model derived parameters such as those that have been presented here. The ability to independently verify these model derived parameters of the sedimentary organic matter undergoing mineralization will likely be important in further refining these models and improving their usefulness in describing (and predicting) the factors controlling organic matter mineralization in marine sediments.