Test of a Model of Organic Matter Preservation in Marine Sediments

9530280 Heinrichs 这项研究将测试一个新模型，该模型通过对沉积物中矿物颗粒的强烈吸附来解释沉积有机物的保存。在模型中，保存取决于不稳定有机物的浓度和溶解速率、溶解有机物的吸附系数、沉积物积累和生物扰动速率以及吸附和溶解有机物的分解速率。该模型不仅解释了有机质保存的全球模式，还解释了海洋环境中陆源有机质和干酪根普遍缺乏保存的情况。 该模型的测试将包括：（1）粘土矿物和氧化铁对蛋白质、聚氨基酸和蛋白黑素的吸附和解吸的测量，（2）沿海沉积物中这些吸附物质的分解研究，以及（3）天然沉积物可水解氨基酸和有机物的吸附测量。 如果得到这项研究结果的支持，所提出的模型将能够解释不同沉积环境中有机质保存的巨大差异，这是全球长期碳、氮和磷循环的关键过程。这将有助于解释近代和古代沉积物中有机质积累的沉积记录。 该模型可以改进对人类活动或自然现象引起的海洋生产力和沉积变化对大陆边缘沉积碳积累影响的预测。

9530280 Heinrichs This research will test a new model which explains sedimentary organic matter preservation in terms of strong adsorption to mineral particles in sediments. In the model, preservation depends on the concentration and solubilization rate of labile organic matter, the adsorption coefficient of dissolved organic substances, the sediment accumulation and bioturbation rates, and the decomposition rates of adsorbed and dissolved organic matter. The model not only explains global patterns of organic matter preservation, but also the general lack of preservation of terrigenous organic matter and kerogen in the marine environment. The test of the model will involve: (1) measurement of adsorption and desorption of proteins, polyamino acids, and melanoidins by clay minerals and iron oxide, (2) studies of the decomposition of these adsorbed substances in coastal sediments, and (3) measurements of the adsorption of natural sediment hydrolyzable amino acids and organic matter. If supported by results of this research, the proposed model would explain the large differences in organic matter preservation in different sedimentary environments, a key process in the long-term global carbon, nitrogen, and phosphorous cycles. This would aid interpretation of the sedimentary record of organic matter accumulation in both recent and ancient sediments. The model could improve predictions of the effects of changes in ocean productivity and sedimentation, due to human activities or natural phenomena, on sedimentary carbon accumulation in continental margins.