9633456 Martens The burial and preservation of organic matter on the continental margins of the world ocean is a process of global importance. In fact, burial out of direct contact with the atmosphere is responsible not only for the deposits of fossil organic matter found throughout the world but also for the persistence of molecular oxygen in the Earth's atmosphere. Understanding the factors impacting the decomposition, preservation, and burial of perimarine organic matter has understandably been one of the classical problems of low-temperature geochemistry. In this project, a group of biogeochemists will be continuing their work on this problem of environmental and economic importance. In this next phase of their research, the focus will be on the relationship of organic matter decomposition and preservation to organic sorption onto sedimentary grains with large surface areas per unit mass (essentially the very finest components of sediments, such as clay minerals). They will carry out laboratory experiments to complement studies of organic sedimentation, decomposition, and burial and four contrasting inner-shelf field sites characterized by different types and rates of organic input as well as different microbiological and sedimentological characteristics. The researchers expect that this approach will lead to an improved quantitative understanding of the relationship of organic preservation to such variables as organic deposit rate, differences in microbial decomposition processes, adsorption and desorption of dissolved organic matter on mineral grains, and burial rate.