Search for: All records

The transport and transformation of carbon in subseafloor environments is a significant component of past, present, and future global fluxes. Seawater’s dissolved organic matter (DOM) enters the subseafloor and undergoes complex reactions including microbial processing, interactions with the rock matrix, and thermal restructuring and remineralization to carbon dioxide. Large shifts in concentrations, isotopic compositions, and molecular abundances provide a rich source of information about the environments through which fluids have circulated. Broad patterns linking geological settings to the fate of organic molecules can now be drawn, including the wide-scale removal of seawater DOM in ridge-flank systems, and large additions of abiotically synthesized compounds into fluids that interact with mantle rocks. Outstanding questions remain concerning the role of hydrothermal circulation as a source of refractory organic matter and its impact on the isotopic signature of deep oceanic DOM.