Speaker: Prof Caroline Peacock, School of Earth & Environment, University of Leeds
Abstract: The preservation of organic carbon in marine sediments is fundamentally important for Earth’s carbon and oxygen cycles, but the controls on carbon preservation remain unclear. Preservation can be enhanced by limiting exposure of carbon to oxygen, but on continental margins, where the majority of carbon preservation occurs, the relationship between oxygen exposure and burial efficiency is weak. In these environments in particular, additional preservation mechanisms are proposed, including the protection and preservation of carbon with sediment minerals. We show that the sorption of carboxyl-rich carbon [1] and its chemical transformation [2] with reactive forms of iron and manganese provides a hitherto unrecognised mechanism for the stabilisation and preservation of carbon in sediments, such that the flux of iron and manganese into the oceans may provide a new control on planetary climate and oxygenation [2,3].
Sorption and transformation of organic carbon with mineral matricies protects carbon from degradation and enhances its preservation in marine sediments, impacting the global carbon and oxygen scales over past, present and future timescales:
References:
[1] Curti L., Moore O.W., Babakhani P., Xiao K-Q., Woulds C., Bray A.W., Fisher B.J., Kazemian M., Kaulich B., Peacock C.L. (2021) Carboxyl-richness controls organic carbon preservation during coprecipitation with iron (oxyhydr)oxides in the natural environment. Communications Earth & Environment 2:299 https://doi.org/10.1038/s43247-021-00301-9
[2] Moore O.W., Curti L., Woulds C., Bradley J.A., Babakhani P., Mills B.J.W., Homoky W.B., Xiao K-Q., Bray A.W., Fisher B.J., Kazemian M., Kaulich B., Dale A.W., Peacock C.L. (2023) Long term organic carbon preservation enhanced by iron and manganese. Nature 621, 312-317 https://doi.org/10.1038/s41586-023-06325-9
[3] Zhao M., Mills B.J.W., Homoky W.B., Peacock C.L. (2023) Oxygenation of the Earth aided by mineral-organic carbon preservation. Nature Geoscience 16, 262-267 https://doi.org/10.1038/s41561-023-01133-2
Venue: Seminar rooms or join online via Zoom link
If you are external to the Department of Earth Sciences and wish to receive information about departmental seminars please join our mailing list by sending a message to: earth_sciences_seminar-request@maillist.ox.ac.uk