粘土矿物保存海洋沉积有机质研究进展及其碳循环意义

Summary of Processes and Significance of Clay Minerals in Marine Sedimentary Organic Matter Preservation and in Global Carbon Cycle

海洋沉积物吸附有机质的量和有机质循环周期与粘土矿物类型和吸附方式密切相关,并在全球碳循环中扮演着不同的角色。粘土吸附有机质有物理吸附和化学吸附之分,前者主要存在于粘土的微孔隙中,参与年、十年或百年尺度的循环;后者主要存在于粘土矿物层间和外表面,稳定性较好,有机质易于保存,可参与百万年或更长时间的循环,这种不同时间尺度内的碳循环,将会改写海洋沉积物有机碳“源”、“汇”的关系。不同类型粘土矿物的性质存在差异,决定了吸附有机质量的多寡,蒙脱石的吸附量远大于伊利石的吸附量,这可能是造成全球不同海域中有机碳“源”、“汇”变化的原因。海洋沉积物处于水圈、生物圈和岩石圈的交汇地带,有机碳的差异和变化,都会对全球碳循环及气候变化产生重要的影响。

In the past decade, a series of progresses have been achieved in interaction between marine sedimentary organic matter and clay minerals. Research advances are summarized in the preservation of marine sediment organic matter by clay minerals adsorption, and its significance in global carbon cycle is discussed thereafter. Adsorption of organic matter to clay minerals occurs everywhere in nature. Organic matter can be adsorbed not only by small intercrystalline mesopores with van der waals force and chemical bonds, but also by interlayer spaces with surface bondage. Adsorption ability of clay minerals is related to types and structures, component and characteristic of organic matter, as well as physicochemistry condition of agential. It was suggested that clay minerals play an important role in protecting marine sedimentary organic matter by adsorption. Sedimentary and buried organic matter can be effectively protected from enzymes by decreasing mesopores of clay minerals after absorption of organic matter. Being a tie between activity carbon reservoir and permanent carbon reservoir, clay minerals in marine sediments translate carbon of atmosphere and ocean reservoir with rapid cycle into lithosphere reservoir via adsorbing organic matter, leading to missing carbon sink. Thus, clay minerals control function of carbon source and sink of oceans and have great influence on global carbon cycle and climate change.