Manganese Limitation of Phytoplankton Physiology and Productivity in the Southern Ocean

Hawco, Nicholas J, Tagliabue, Alessandro ORCID: 0000-0002-3572-3634 and Twining, Benjamin S (2022) Manganese Limitation of Phytoplankton Physiology and Productivity in the Southern Ocean. GLOBAL BIOGEOCHEMICAL CYCLES, 36 (11). e2022GB007382-.

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Official URL: http://dx.doi.org/10.1029/2022gb007382

Abstract

Although iron and light are understood to regulate the Southern Ocean biological carbon pump, observations have also indicated a possible role for manganese. Low concentrations in Southern Ocean surface waters suggest manganese limitation is possible, but its spatial extent remains poorly constrained and direct manganese limitation of the marine carbon cycle has been neglected by ocean models. Here, using available observations, we develop a new global biogeochemical model and find that phytoplankton in over half of the Southern Ocean cannot attain maximal growth rates because of manganese deficiency. Manganese limitation is most extensive in austral spring and depends on phytoplankton traits related to the size of photosynthetic antennae and the inhibition of manganese uptake by high zinc concentrations in Antarctic waters. Importantly, manganese limitation expands under the increased iron supply of past glacial periods, reducing the response of the biological carbon pump. Overall, these model experiments describe a mosaic of controls on Southern Ocean productivity that emerge from the interplay of light, iron, manganese and zinc, shaping the evolution of Antarctic phytoplankton since the opening of the Drake Passage.

Item Type:	Article
Uncontrolled Keywords:	carbon export, diatoms, nutrient limitation, photosynthesis, subantarctic, trace metals
Divisions:	Faculty of Science and Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	21 Mar 2023 10:27
Last Modified:	14 Apr 2023 05:20
DOI:	10.1029/2022GB007382
Open Access URL:	https://agupubs.onlinelibrary.wiley.com/doi/full/1...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3169181