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Spatial and seasonal distribution of dissolved and particulate bioactive metals in Antarctic sea ice

Citation

Duprat, L and Townsend, AT and van der Merwe, P and Meiners, KM and Lannuzel, D, Spatial and seasonal distribution of dissolved and particulate bioactive metals in Antarctic sea ice, Elementa, 9, (1) Article 00032. ISSN 2325-1026 (2021) [Refereed Article]


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Copyright Statement

Copyright: 2021 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.

DOI: doi:10.1525/elementa.2021.00032

Abstract

Iron (Fe) has been shown to limit growth of marine phytoplankton in the Southern Ocean, regulating phytoplankton productivity and species composition, yet does not seem to limit primary productivity in Antarctic sea ice. Little is known, however, about the potential impact of other metals in controlling sea-ice algae growth. Here, we report on the distribution of dissolved and particulate cadmium (Cd), cobalt (Co), copper (Cu), manganese (Mn), nickel (Ni), and zinc (Zn) concentrations in sea-ice cores collected during 3 Antarctic expeditions off East Antarctica spanning the winter, spring, and summer seasons. Bulk sea ice was generally enriched in particulate metals but dissolved concentrations were similar to the underlying seawater. These results point toward an environment controlled by a subtle balance between thermodynamic and biological processes, where metal availability does not appear to limit sea-ice algal growth. Yet the high concentrations of dissolved Cu and Zn found in our sea-ice samples raise concern about their potential toxicity if unchelated by organic ligands. Finally, the particulate metal-to-phosphorus (P) ratios of Cu, Mn, Ni, and Zn calculated from our pack ice samples are higher than values previously reported for pelagic marine particles. However, these values were all consistently lower than the sea-ice Fe:P ratios calculated from the available literature, indicating a large accumulation of Fe relative to other metals in sea ice. We report for the first time a P-normalized sea-ice particulate metal abundance ranking of Fe >> Zn ≈ Ni ≈ Cu ≈ Mn > Co ≈ Cd. We encourage future sea-ice work to assess cellular metal quotas through existing and new approaches. Such work, together with a better understanding of the nature of ligand complexation to different metals in the sea-ice environment, would improve the evaluation of metal bioavailability, limitation, and potential toxicity to sea-ice algae.

Item Details

Item Type:Refereed Article
Keywords:sea ice, East-Antarctica, metals, sea-ice algae, limitation, toxicity
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Duprat, L (Mr Duprat)
UTAS Author:Townsend, AT (Associate Professor Ashley Townsend)
UTAS Author:van der Merwe, P (Dr Pier van der Merwe)
UTAS Author:Lannuzel, D (Associate Professor Delphine Lannuzel)
ID Code:151388
Year Published:2021
Deposited By:Oceans and Cryosphere
Deposited On:2022-07-28
Last Modified:2022-08-05
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