University of Tasmania
Browse

File(s) under permanent embargo

Elemental quotas and physiology of a southwestern Pacific Ocean plankton community as a function of iron availability

journal contribution
posted on 2023-05-18, 04:00 authored by Wilhelm, SW, King, AL, Twining, BS, LeCleir, GR, DeBruyn, JM, Robert StrzepekRobert Strzepek, Breene, CL, Pickmere, S, Ellwood, MJ, Philip BoydPhilip Boyd, Hutchins, DA
The rate of carbon fixation by phytoplankton in marine surface waters is often tied to the supply of growth-limiting nutrients such as iron (Fe). While average cellular requirements and ratios for various elements are well known in the literature, especially through laboratory culture work, the plasticity of these relationships in natural plankton communities has been less explored. To gauge how changes in the biological availability of dissolved Fe might influence cellular nutrient ratios of marine phytoplankton (and thus their physiology), we carried out incubation assays during a research expedition off the east coast of New Zealand. Trace-metal clean collection of plankton communities were amended with a continuum of concentrations of either Fe (as FeCl3) or desferroxamine B (to reduce bioavailable Fe) and then maintained for 72 h under in situ conditions. Along with standard assays (Fv/Fm, chlorophyll, nutrient drawdown), we measured elemental ratios in the bulk community by inductively coupled plasma mass spectrometry and within individual plankton using synchrotron X-ray fluorescence. Our observations demonstrate that changes in the physiological ecology of the community (biomass, photosynthetic efficiency) were mirrored in changes in elemental ratios, including a 3-fold change in Fe stoichiometry and a 13-fold change in Zn stoichiometry when Fe-replete and Fe-depleted communities were compared. We present this information in consideration of the hypothesis that flexibility in elemental quotas influences the interactions between nutrient availability and planktonic physiological status, subsequently altering C flow through marine surface waters.

History

Publication title

Aquatic Microbial Ecology

Volume

68

Pagination

185-194

ISSN

0948-3055

Department/School

Institute for Marine and Antarctic Studies

Publisher

Inter-Research

Place of publication

Nordbunte 23, Oldendorf Luhe, Germany, D-21385

Rights statement

Copyright 2013 Inter-Research

Repository Status

  • Restricted

Socio-economic Objectives

Atmospheric composition (incl. greenhouse gas inventory)

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC