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Abstract

Zinc (Zn) isotope fractionation by the coccolithophore Emiliania huxleyi (a Tasman Sea isolate) was investigated by culturing it across a range of free Zn2+ ion concentrations (1.2 pmol L−1 to 3.2 nmol L−1), which span the natural range observed in the global oceans. Across the range of free Zn2+ ion concentrations tested, the amount of bio-available Zn did not have any appreciable influence on the specific growth rate or cell morphology of E. huxleyi. However, a suite of secondary physiological indicators reflected changes in Zn bioavailability. An increase in the photosynthetic efficiency of photosystem II (Fv/Fm) was observed with increasing free Zn2+ ion concentration. The time constants for electron transport from QA to QB and from QB to the plastoquinone (PQ) pool decreased as the free Zn2+ ion concentration increased, reflecting enhanced photosynthetic electron transport. The effect of Zn bioavailability on photosynthetic physiology was speculated to be due to increased activity of carbonic anhydrase with increasing Zn bioavailability. Zinc uptake by E. huxleyi resulted in Zn isotope fractionation and the Δ66Zncells-media ranged between −0.6‰ and −0.2‰. The major finding from this work is that the lighter Zn isotope is taken up preferentially by this coccolithophore, making the dissolved Zn composition of the surrounding seawater isotopically heavier.

Item Type:	Article
Authors/Creators:	Samanta, M and Ellwood, MJ and Strzepek, RF
Keywords:	zinc, isotope, fractionation, Emiliania huxleyi, coccolithophore
Journal or Publication Title:	Limnology and Oceanography
Publisher:	Amer Soc Limnology Oceanography
ISSN:	0024-3590
DOI / ID Number:	https://doi.org/10.1002/lno.10658
Copyright Information:	Copyright 2017 Association for the Sciences of Limnology and Oceanography
Related URLs:	Google Scholar: Strzepek, RF
Item Statistics:	View statistics for this item

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