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Abstract

Surface ocean availability of the micronutrients iron and manganese influences primary productivity and carbon cycling in the ocean. Volcanic ash is rich in iron and manganese, but the global supply of these nutrients to the oceans via ash deposition is poorly constrained. Here, we use marine sediment-hosted ash composition data from ten volcanic regions, and subaerial volcanic eruption volumes, to estimate global ash-driven nutrient fluxes. Using Monte Carlo simulations, we estimate average fluxes of dissolved Iron and Manganese from volcanic sources to be between 50 and 500 (median 180) and 0.6 and 3.2 (median 1.3) Gmol yr−1, respectively. Much of the element release occurs during early diagenesis, indicating ash-rich shelf sediments are likely important suppliers of aqueous iron and manganese. Estimated ash-driven fluxes are of similar magnitude to aeolian inputs. We suggest that subaerial volcanism is an important, but underappreciated, source of these micronutrients to the global ocean.

Publication Date

2022-03-14

Publication Title

Communications Earth & Environment

Volume

3

ISSN

2662-4435

Acceptance Date

2022-02-18

Deposit Date

2022-02-24

Embargo Period

2022-04-09

Funding

This work was funded by NERC grant, NE/K00543X/1, “The role of marine diagenesis of tephra in the carbon cycle”. M.T.J. was supported by the Research Council of Norway, project numbers 263000 and 223272. T.G. was supported by NERC grant, NE/R004978/1, and the Alan Turing Institute (under EP/N510129/1).

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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