Horner, TJ;
Little, SH;
Conway, TM;
Farmer, JR;
Hertzberg, JE;
Janssen, DJ;
Lough, AJM;
... Members, GEOTRACESAGESBP; + view all
(2021)
Bioactive trace metals and their isotopes as paleoproductivity proxies: An assessment using GEOTRACES‐era data.
Global Biogeochemical Cycles
, Article e2020GB006814. 10.1029/2020gb006814.
(In press).
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Abstract
Phytoplankton productivity and export sequester climatically significant quantities of atmospheric carbon dioxide as particulate organic carbon through a suite of processes termed the biological pump. How the biological pump operated in the past is therefore important for understanding past atmospheric carbon dioxide concentrations and Earth’s climate history. However, reconstructing the history of the biological pump requires proxies. Due to their intimate association with biological processes, several bioactive trace metals and their isotopes are potential proxies for past phytoplankton productivity, including: iron, zinc, copper, cadmium, molybdenum, barium, nickel, chromium, and silver. Here we review the oceanic distributions, driving processes, and depositional archives for these nine metals and their isotopes based on GEOTRACES-era datasets. We offer an assessment of the overall maturity of each isotope system to serve as a proxy for diagnosing aspects of past ocean productivity and identify priorities for future research. This assessment reveals that cadmium, barium, nickel, and chromium isotopes offer the most promise as tracers of paleoproductivity, whereas iron, zinc, copper, and molybdenum do not. Too little is known about silver to make a confident determination. Intriguingly, the elements that are least sensitive to productivity may be used to trace other aspects of ocean chemistry, such as nutrient sources, particle scavenging, organic complexation, and ocean redox state. These complementary sensitivities suggest new opportunities for combining perspectives from multiple proxies that will ultimately enable painting a more complete picture of marine paleoproductivity, biogeochemical cycles, and Earth’s climate history.
| Type: | Article |
|---|---|
| Title: | Bioactive trace metals and their isotopes as paleoproductivity proxies: An assessment using GEOTRACES‐era data |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2020gb006814 |
| Publisher version: | https://doi.org/10.1029/2020GB006814 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Biological pump; marine chemistry; biogeochemical cycles; micronutrients; phytoplankton; paleoceanography |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10128907 |
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