Effects of iron limitation on silicon uptake kinetics and elemental stoichiometry in two Southern Ocean diatoms, Eucampia antarctica and Proboscia inermis, and the temperate diatom Thalassiosira pseudonana

S.W. Meyerink, M.J. Ellwood, W.A. Maher, G. Dean Price, R.F. Strzepek

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    Abstract

    We investigated the effects of iron (Fe) limitation on the elemental stoichiometry, silicic acid (Si(OH)4) uptake kinetics and cell morphology in two Southern Ocean diatoms Eucampia antarctica and Proboscia inermis and the temperate diatom Thalassiosira pseudonana. An increase in Fe-stress resulted in reductions in specific growth rate and decreases in cellular nitrogen (N) and carbon (C) content relative to cellular biogenic silica (BSi) in both Southern Ocean diatoms and a reduction in growth rate only for T. pseudonana. Both E. antarctica and P. inermis exhibited an increase in cell volume in response to Fe-limitation resulting in a decrease in the cell surface to volume ratio, while normalization of BSi content to cell surface area suggests these diatoms do not become more heavily silicified under Fe limitation. Kinetic Si(OH)4 uptake experiments performed on all three diatom species show that Si(OH)4 uptake is reduced under Fe-limited conditions. For Southern Ocean diatoms, this was manifested through a decrease in the maximum specific uptake rate of Si(OH)4 (VSi-max), along with a decrease in the half-saturation constant for Si(OH)4 uptake (KSi) under Fe stress for E. antarctica. Our data also show that when normalized to cell surface area, VSi-max of the three diatoms species exhibited a linear relationship with cellular growth rate, and was independent of cell morphological variations. Our results suggest that the morphological adaptations of Southern Ocean diatoms in response to Fe-stress have the potential to affect phytoplankton community dynamics and Si(OH)4 : NO3 uptake and export ratios in Southern Ocean waters. © 2017 Association for the Sciences of Limnology and Oceanography
    Original languageUndefined
    Pages (from-to)2445-2462
    Number of pages18
    JournalLimnology and Oceanography
    Volume62
    Issue number6
    DOIs
    Publication statusPublished - 2017

    Cite this

    @article{cc3f7bbfdbaf451d87e54aad4eb78a28,
    title = "Effects of iron limitation on silicon uptake kinetics and elemental stoichiometry in two Southern Ocean diatoms, Eucampia antarctica and Proboscia inermis, and the temperate diatom Thalassiosira pseudonana",
    abstract = "We investigated the effects of iron (Fe) limitation on the elemental stoichiometry, silicic acid (Si(OH)4) uptake kinetics and cell morphology in two Southern Ocean diatoms Eucampia antarctica and Proboscia inermis and the temperate diatom Thalassiosira pseudonana. An increase in Fe-stress resulted in reductions in specific growth rate and decreases in cellular nitrogen (N) and carbon (C) content relative to cellular biogenic silica (BSi) in both Southern Ocean diatoms and a reduction in growth rate only for T. pseudonana. Both E. antarctica and P. inermis exhibited an increase in cell volume in response to Fe-limitation resulting in a decrease in the cell surface to volume ratio, while normalization of BSi content to cell surface area suggests these diatoms do not become more heavily silicified under Fe limitation. Kinetic Si(OH)4 uptake experiments performed on all three diatom species show that Si(OH)4 uptake is reduced under Fe-limited conditions. For Southern Ocean diatoms, this was manifested through a decrease in the maximum specific uptake rate of Si(OH)4 (VSi-max), along with a decrease in the half-saturation constant for Si(OH)4 uptake (KSi) under Fe stress for E. antarctica. Our data also show that when normalized to cell surface area, VSi-max of the three diatoms species exhibited a linear relationship with cellular growth rate, and was independent of cell morphological variations. Our results suggest that the morphological adaptations of Southern Ocean diatoms in response to Fe-stress have the potential to affect phytoplankton community dynamics and Si(OH)4 : NO3 uptake and export ratios in Southern Ocean waters. {\circledC} 2017 Association for the Sciences of Limnology and Oceanography",
    author = "S.W. Meyerink and M.J. Ellwood and W.A. Maher and {Dean Price}, G. and R.F. Strzepek",
    note = "cited By 1",
    year = "2017",
    doi = "10.1002/lno.10578",
    language = "Undefined",
    volume = "62",
    pages = "2445--2462",
    journal = "Limnology and Oceanography",
    issn = "0024-3590",
    publisher = "Wiley-Blackwell",
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    TY - JOUR

    T1 - Effects of iron limitation on silicon uptake kinetics and elemental stoichiometry in two Southern Ocean diatoms, Eucampia antarctica and Proboscia inermis, and the temperate diatom Thalassiosira pseudonana

    AU - Meyerink, S.W.

    AU - Ellwood, M.J.

    AU - Maher, W.A.

    AU - Dean Price, G.

    AU - Strzepek, R.F.

    N1 - cited By 1

    PY - 2017

    Y1 - 2017

    N2 - We investigated the effects of iron (Fe) limitation on the elemental stoichiometry, silicic acid (Si(OH)4) uptake kinetics and cell morphology in two Southern Ocean diatoms Eucampia antarctica and Proboscia inermis and the temperate diatom Thalassiosira pseudonana. An increase in Fe-stress resulted in reductions in specific growth rate and decreases in cellular nitrogen (N) and carbon (C) content relative to cellular biogenic silica (BSi) in both Southern Ocean diatoms and a reduction in growth rate only for T. pseudonana. Both E. antarctica and P. inermis exhibited an increase in cell volume in response to Fe-limitation resulting in a decrease in the cell surface to volume ratio, while normalization of BSi content to cell surface area suggests these diatoms do not become more heavily silicified under Fe limitation. Kinetic Si(OH)4 uptake experiments performed on all three diatom species show that Si(OH)4 uptake is reduced under Fe-limited conditions. For Southern Ocean diatoms, this was manifested through a decrease in the maximum specific uptake rate of Si(OH)4 (VSi-max), along with a decrease in the half-saturation constant for Si(OH)4 uptake (KSi) under Fe stress for E. antarctica. Our data also show that when normalized to cell surface area, VSi-max of the three diatoms species exhibited a linear relationship with cellular growth rate, and was independent of cell morphological variations. Our results suggest that the morphological adaptations of Southern Ocean diatoms in response to Fe-stress have the potential to affect phytoplankton community dynamics and Si(OH)4 : NO3 uptake and export ratios in Southern Ocean waters. © 2017 Association for the Sciences of Limnology and Oceanography

    AB - We investigated the effects of iron (Fe) limitation on the elemental stoichiometry, silicic acid (Si(OH)4) uptake kinetics and cell morphology in two Southern Ocean diatoms Eucampia antarctica and Proboscia inermis and the temperate diatom Thalassiosira pseudonana. An increase in Fe-stress resulted in reductions in specific growth rate and decreases in cellular nitrogen (N) and carbon (C) content relative to cellular biogenic silica (BSi) in both Southern Ocean diatoms and a reduction in growth rate only for T. pseudonana. Both E. antarctica and P. inermis exhibited an increase in cell volume in response to Fe-limitation resulting in a decrease in the cell surface to volume ratio, while normalization of BSi content to cell surface area suggests these diatoms do not become more heavily silicified under Fe limitation. Kinetic Si(OH)4 uptake experiments performed on all three diatom species show that Si(OH)4 uptake is reduced under Fe-limited conditions. For Southern Ocean diatoms, this was manifested through a decrease in the maximum specific uptake rate of Si(OH)4 (VSi-max), along with a decrease in the half-saturation constant for Si(OH)4 uptake (KSi) under Fe stress for E. antarctica. Our data also show that when normalized to cell surface area, VSi-max of the three diatoms species exhibited a linear relationship with cellular growth rate, and was independent of cell morphological variations. Our results suggest that the morphological adaptations of Southern Ocean diatoms in response to Fe-stress have the potential to affect phytoplankton community dynamics and Si(OH)4 : NO3 uptake and export ratios in Southern Ocean waters. © 2017 Association for the Sciences of Limnology and Oceanography

    U2 - 10.1002/lno.10578

    DO - 10.1002/lno.10578

    M3 - Article

    VL - 62

    SP - 2445

    EP - 2462

    JO - Limnology and Oceanography

    JF - Limnology and Oceanography

    SN - 0024-3590

    IS - 6

    ER -