Test of a Model of Organic Matter Preservation in Marine Sediments

9530280海因里希斯 这项研究将测试一个新的模型，该模型解释了沉积有机质保存在沉积物中的矿物颗粒的强吸附。在该模型中，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，而且还解释了海洋环境中陆源有机质和干酪根保存的普遍缺乏。 模型的检验包括：（1）测定粘土矿物和氧化铁对蛋白质、多聚氨基酸和类黑精的吸附和解吸，（2）研究这些吸附物质在海岸沉积物中的分解，（3）测定天然沉积物中可水解氨基酸和有机质的吸附。 如果得到这项研究结果的支持，所提出的模型将解释不同沉积环境中有机质保存的巨大差异，这是长期全球碳，氮和磷循环的关键过程。这将有助于解释现代和古代沉积物中有机质积累的沉积记录。 该模型可以更好地预测人类活动或自然现象造成的海洋生产力和沉积作用的变化对大陆边沉积碳积累的影响。

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.