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150790 - Southern Ocean phytoplankton stimulated by wildfire emissions.pdf (1.67 MB)

Southern Ocean phytoplankton stimulated by wildfire emissions and sustained by iron recycling

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Large ash plumes emitted by the 2019–2020 Australian wildfires were associated with a widespread phytoplankton bloom in the iron-limited Pacific sector of the Southern Ocean. In this study, we used satellite observations and aerosol reanalysis products to study the regional phytoplankton community response to wildfire emissions. The bloom was stimulated by pyrogenic iron fertilization and coincided with elevated cellular pigment concentrations, increased photochemical efficiency, and apparent community structural shifts. Physiological anomalies were consistent with previously observed phytoplankton responses to iron stress relief and persisted for up to 9 months. Supported by a regional iron budget, we conclude that the bloom was sustained by iron recycling and episodic inputs of pyrogenic and dust-borne mineral iron. The continuous regeneration of iron was likely facilitated by the bloom's large size, mitigating edge dilution effects, as well as enhanced bioavailability of pyrogenic and mineral iron due to atmospheric and chemical processing during long-range transport.

Funding

Australian Research Council

History

Publication title

Geophysical Research Letters

Volume

49

Issue

11

Article number

e2021GL097538

Number

e2021GL097538

Pagination

1-11

ISSN

0094-8276

Department/School

Institute for Marine and Antarctic Studies

Publisher

Amer Geophysical Union

Place of publication

2000 Florida Ave Nw, Washington, USA, Dc, 20009

Rights statement

© 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, (https://creativecommons.org/licenses/by-nc-nd/4.0/) which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Repository Status

  • Open

Socio-economic Objectives

Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts); Expanding knowledge in the earth sciences