Marine sediments are the most significant OC reservoir in the Earth's surface system. Iron, a crucial component of the marine biogeochemical cycle, has a considerable impact on marine ecology and carbon cycling. Understanding the effect of iron on the preservation of OC inis essential for comprehending biogeochemical processes of carbon sequestration and climate change.
The figure illustrates the dual role of iron in the redox reactions and preservation/ degradation of OC in marine sedimentary environments. It emphasizes the significant effect of early diagenetic redox zonation and the iron sulfides on the selective preservation and degradation of OC. Credit: Science China Press
This review summarizes the methods for characterizing the occurrence and structure of iron-bound OC and explores the influencing mechanism of iron on OC preservation in marine sediments from two aspects: the selective preservation of OC by reactive iron minerals and iron redox processes. By considering sedimentary records of iron-bound OC across diverse marine environments, the role of iron in long-term preservation of OC and its significance for carbon sequestration are illustrated.
Future research should focus on identifying effective methods for extracting reactive iron, the effect of diverse functional groups and marine sedimentary environments on the selective preservation of OC, and the mediation of microorganisms.