Articles | Volume 20, issue 24
https://doi.org/10.5194/bg-20-5003-2023
https://doi.org/10.5194/bg-20-5003-2023
Research article
 | 
19 Dec 2023
Research article |  | 19 Dec 2023

Revisiting the applicability and constraints of molybdenum- and uranium-based paleo redox proxies: comparing two contrasting sill fjords

K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert

Related authors

Drought recorded by Ba∕Ca in coastal benthic foraminifera
Inda Brinkmann, Christine Barras, Tom Jilbert, Tomas Næraa, K. Mareike Paul, Magali Schweizer, and Helena L. Filipsson
Biogeosciences, 19, 2523–2535, https://doi.org/10.5194/bg-19-2523-2022,https://doi.org/10.5194/bg-19-2523-2022, 2022
Short summary

Related subject area

Biogeochemistry: Coastal Ocean
Ocean alkalinity enhancement (OAE) does not cause cellular stress in a phytoplankton community of the subtropical Atlantic Ocean
Librada Ramírez, Leonardo J. Pozzo-Pirotta, Aja Trebec, Víctor Manzanares-Vázquez, José L. Díez, Javier Arístegui, Ulf Riebesell, Stephen D. Archer, and María Segovia
Biogeosciences, 22, 1865–1886, https://doi.org/10.5194/bg-22-1865-2025,https://doi.org/10.5194/bg-22-1865-2025, 2025
Short summary
Reviews and syntheses: On increasing hypoxia in eastern boundary upwelling systems – zooplankton under metabolic stress
Leissing Frederick, Mauricio A. Urbina, and Ruben Escribano
Biogeosciences, 22, 1839–1852, https://doi.org/10.5194/bg-22-1839-2025,https://doi.org/10.5194/bg-22-1839-2025, 2025
Short summary
Technical note: Testing a new approach for the determination of N2 fixation rates by coupling a membrane equilibrator to a mass spectrometer for long-term observations
Sören Iwe, Oliver Schmale, and Bernd Schneider
Biogeosciences, 22, 1767–1779, https://doi.org/10.5194/bg-22-1767-2025,https://doi.org/10.5194/bg-22-1767-2025, 2025
Short summary
Long-term variations in pH in coastal waters along the Korean Peninsula
Yong-Woo Lee, Mi-Ok Park, Seong-Gil Kim, Tae-Hoon Kim, Yong Hwa Oh, Sang Heon Lee, and DongJoo Joung
Biogeosciences, 22, 675–690, https://doi.org/10.5194/bg-22-675-2025,https://doi.org/10.5194/bg-22-675-2025, 2025
Short summary
The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes
Kadir Biçe, Tristen Myers Stewart, George G. Waldbusser, and Christof Meile
Biogeosciences, 22, 641–657, https://doi.org/10.5194/bg-22-641-2025,https://doi.org/10.5194/bg-22-641-2025, 2025
Short summary

Cited articles

Adelson, J. M., Helz, G. R., and Miller, C. V.: Reconstructing the rise of recent coastal anoxia; molybdenum in Chesapeake Bay sediments, Geochim. Cosmochim. Ac., 65, 237–252, https://doi.org/10.1016/S0016-7037(00)00539-1, 2001. 
Aksnes, D. L., Aure, J., Johansen, P. O., Johnsen, G. H., and Salvanes, A. G. V.: Multi-decadal warming of Atlantic water and associated decline of dissolved oxygen in a deep fjord, Estuar. Coast. Shelf. S., 228, 106392, https://doi.org/10.1016/j.ecss.2019.106392, 2019. 
Alessi, D. S., Lezama-Pacheco, J. S., Stubbs, J. E., Janousch, M., Bargar, J. R., Persson, P., and Bernier-Latmani, R.: The product of microbial uranium reduction includes multiple species with U(IV)-phosphate coordination, Geochim. Cosmochim. Ac., 131, 115–127, https://doi.org/10.1016/j.gca.2014.01.005, 2014. 
Alessi, D. S., Uster, B., Veeramani, H., Suvorova, E. I., Lezama-Pacheco, J. S., Stubbs, J. E., Bargar, J. R., and Bernier-Latmani, R.: Quantitative separation of monomeric U(IV) from UO2 in products of U(VI) reduction, Environ. Sci. Technol., 46, 6150–6157, https://doi.org/10.1021/es204123z, 2012. 
Algeo, T. J. and Li, C.: Redox classification and calibration of redox thresholds in sedimentary systems, Geochim. Cosmochim. Ac., 287, 8–26, https://doi.org/10.1016/j.gca.2020.01.055, 2020. 
Download
Short summary
Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Share
Altmetrics
Final-revised paper
Preprint