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Iron availability influences silicon isotope fractionation in two Southern Ocean diatoms (Proboscia inermis and Eucampia antarctica) and a coastal diatom (Thalassiosira pseudonana)


Meyerink, S and Ellwood, MJ and Maher, WA and Strzepek, R, Iron availability influences silicon isotope fractionation in two Southern Ocean diatoms (Proboscia inermis and Eucampia antarctica) and a coastal diatom (Thalassiosira pseudonana), Frontiers in Marine Science, 4 Article 217. ISSN 2296-7745 (2017) [Refereed Article]

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Copyright 2017 Meyerink, Ellwood, Maher and Strzepek. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License ( The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

DOI: doi:10.3389/fmars.2017.00217


The fractionation of silicon (Si) isotopes was measured in two Southern Ocean diatoms (Proboscia inermis and Eucampia Antarctica) and a coastal diatom (Thalassiosira pseudonana) that were grown under varying iron (Fe) concentrations. Varying Fe concentrations had no effect on the Si isotope enrichment factor (ε) in T. pseudonana, whilst E. Antarctica and P. inermis exhibited significant variations in the value of ε between Fe-replete and Fe-limited conditions. Mean ε values in P. inermis and E. Antarctica decreased from ( 1SD) −1.11 0.15 and −1.42 0.41 (respectively) under Fe-replete conditions, to −1.38 0.27 and −1.57 0.5 (respectively) under Fe-limiting conditions. These variations likely arise from adaptations in diatoms arising from the nutrient status of their environment. T. pseudonana is a coastal clone typically accustomed to low Si but high Fe conditions whereas E. Antarctica and P. inermis are typically accustomed to High Si, High nitrate low Fe conditions. Growth induced variations in silicic acid (Si(OH)4) uptake arising from Fe-limitation is the likely mechanism leading to Si-isotope variability in E. Antarctica and P. inermis. The multiplicative effects of species diversity and resource limitation (e.g., Fe) on Si-isotope fractionation in diatoms can potentially alter the Si-isotope composition of diatom opal in diatamaceous sediments and sea surface Si(OH)4. This work highlights the need for further in vitro studies into intracellular mechanisms involved in Si(OH)4 uptake, and the associated pathways for Si-isotope fractionation in diatoms.

Item Details

Item Type:Refereed Article
Keywords:silicon isotopes, Southern Ocean, diatom, isotope fractionation, iron
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Strzepek, R (Dr Robert Strzepek)
ID Code:148043
Year Published:2017
Web of Science® Times Cited:10
Deposited By:Australian Antarctic Program Partnership
Deposited On:2021-11-30
Last Modified:2022-08-24
Downloads:7 View Download Statistics

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