Abstract

Carbon is removed from Earth’s surface during the burial and subsequent lithification of carbon bearing minerals, primarily organic carbon (the breakdown of living organisms) and carbonate (also known as calcite or limestone). When carbon bearing minerals are added to sediments however, they continue to undergo chemical reactions as they are buried beneath the ocean floor; sediments are a large chemical and biological reactor. The deep biosphere in marine sediments comprises the bacteria and archaea living largely in the absence of oxygen; the deep biosphere is responsible for the oxidation of the vast majority of organic carbon that arrives onto marine sediments. I will discuss the use of geochemical measurements in fluids and minerals from marine sediments as a mechanism for studying processes within the deep biosphere and their impact on global ocean chemistry and the carbon cycle.