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Transformation of iodate to iodide in marine phytoplankton driven by cell senescence


Bluhm, K and Croot, P and Wuttig, K and Lochte, K, Transformation of iodate to iodide in marine phytoplankton driven by cell senescence, Aquatic Biology, 11, (1) pp. 1-15. ISSN 1864-7782 (2010) [Refereed Article]

Copyright Statement

Copyright 2010 Inter-Research

DOI: doi:10.3354/ab00284


Previous studies have suggested that phytoplankton play an important role in the biogeochemical cycling of iodine, due to the appearance of iodide in the euphotic zone. Changes in the speciation of iodine over the course of the growth cycle were examined in culture media for a variety of phytoplankton taxa (diatoms, dinoflagellates and prymnesiophytes). All species tested showed the apparent ability to reduce iodate to iodide, though production rates varied considerably between species (0.01 to 0.26 nmol l1 g1 chl a d1), with Eucampia antarctica the least and Pseudo-nitzschia turgiduloides the most efficient iodide producers. Production was found to be species specific and was not related to biomass (indicated by e.g. cell size, cell volume, or chl a content). In all species, except for the mixotrophic dinoflagellate Scrippsiella trochoidea, iodide production commenced in the stationary growth phase and peaked in the senescent phase of the algae, indicating that iodide production is connected to cell senescence. This suggests that iodate reduction results from increased cell permeability, which we hypothesize is due to subsequent reactions of iodate with reduced sulphur species exuded from the cell. A shift from senescence back to the exponential growth phase resulted in a decline in iodide and indicated that phytoplankton-mediated oxidation of iodide to iodate was likely to be occurring. Iodide production could not be observed in healthy cells kept in the dark for short periods. Bacterial processes appeared to play only a minor role in the reduction of iodate to iodide.

Item Details

Item Type:Refereed Article
Keywords:iodine speciation, iodide, iodate, Antarctic diotoms, nitrate reductase, glutathione, sulphur species, cell senescence
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:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Wuttig, K (Dr Kathrin Wuttig)
ID Code:103230
Year Published:2010
Web of Science® Times Cited:41
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2015-09-29
Last Modified:2015-10-13

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