| Title: |
Assessment of C, N, and Si Isotopes as Tracers of Past Ocean Nutrient and Carbon Cycling |
| Authors: |
Farmer, J. R.; Hertzberg, J. E.; Cardinal, D.; Fietz, S.; Hendry, K.; Jaccard, S. L.; Paytan, A.; Rafter, P. A.; Ren, H.; Somes, C. J.; Sutton, J. N.; GEOTRACES PAGES Biological Productivity Working Group Members; 4 LOCEAN (UMR7159) Sorbonne Université IRD CNRS MNHN Paris France; 5 Department of Earth Sciences Stellenbosch University Stellenbosch South Africa; 6 School of Earth Sciences University of Bristol Bristol UK; 7 Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern Bern Switzerland; 9 Institute of Marine Sciences University of California, Santa Cruz Santa Cruz CA USA; 10 Department of Earth System Science University of California Irvine CA USA; 11 Department of Geosciences National Taiwan University Taipei Taiwan; 12 GEOMAR Helmholtz Centre for Ocean Research Kiel Kiel Germany; 13 University of Brest CNRS IRD Ifremer Institut Universitaire Européen de la Mer LEMAR Plouzané France; 14 A full list of working group members and their affiliations appears at the Appendix A |
| Publication Year: |
2021 |
| Collection: |
GEO-LEOe-docs (SUB Göttingen / TU Bergakademie Freiberg) |
| Subject Terms: |
ddc:551.9; marine chemistry; carbon; nitrogen; silicon; paleoceanography; stable isotopes |
| Description: |
Biological productivity in the ocean directly influences the partitioning of carbon between the atmosphere and ocean interior. Through this carbon cycle feedback, changing ocean productivity has long been hypothesized as a key pathway for modulating past atmospheric carbon dioxide levels and hence global climate. Because phytoplankton preferentially assimilate the light isotopes of carbon and the major nutrients nitrate and silicic acid, stable isotopes of carbon (C), nitrogen (N), and silicon (Si) in seawater and marine sediments can inform on ocean carbon and nutrient cycling, and by extension the relationship with biological productivity and global climate. Here, we compile water column C, N, and Si stable isotopes from GEOTRACES‐era data in four key ocean regions to review geochemical proxies of oceanic carbon and nutrient cycling based on the C, N, and Si isotopic composition of marine sediments. External sources and sinks as well as internal cycling (including assimilation, particulate matter export, and regeneration) are discussed as likely drivers of observed C, N, and Si isotope distributions in the ocean. The potential for C, N, and Si isotope measurements in sedimentary archives to record aspects of past ocean C and nutrient cycling is evaluated, along with key uncertainties and limitations associated with each proxy. Constraints on ocean C and nutrient cycling during late Quaternary glacial‐interglacial cycles and over the Cenozoic are examined. This review highlights opportunities for future research using multielement stable isotope proxy applications and emphasizes the importance of such applications to reconstructing past changes in the oceans and climate system. ; Plain Language Summary: The ability of marine phytoplankton to fix carbon—and hence influence the air‐sea partitioning of the greenhouse gas carbon dioxide—highlights the potential for these organisms to influence global climate in the past and future. In addition to C, phytoplankton require nutrients including inorganic N and for ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1029/2020GB006775 |
| Availability: |
https://doi.org/10.1029/2020GB006775; http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/9533 |
| Rights: |
This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
| Accession Number: |
edsbas.51DDF1C2 |
| Database: |
BASE |