Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton
The role of marine organisms in the redox cycling of iodine in the ocean is not well understood presently. Previous studies have suggested that phytoplankton play an important role in the biogeochemical cycling of iodine, and were responsible for the appearance of the non thermodynamically favoured...
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ftoceanrep:oai:oceanrep.geomar.de:12452 2023-05-15T18:25:52+02:00 Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton Bluhm, Katrin Croot, Peter Wuttig, Kathrin Lochte, Karin 2011 https://oceanrep.geomar.de/id/eprint/12452/ unknown Bluhm, K., Croot, P., Wuttig, K. and Lochte, K. (2011) Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton. [Talk] In: Goldschmidt Conference 2011. , 14.-19.08.2011, Prague, Czech Republic . Conference or Workshop Item NonPeerReviewed 2011 ftoceanrep 2023-04-07T15:00:56Z The role of marine organisms in the redox cycling of iodine in the ocean is not well understood presently. Previous studies have suggested that phytoplankton play an important role in the biogeochemical cycling of iodine, and were responsible for the appearance of the non thermodynamically favoured species iodide in the euphotic zone. A key question that arises however is how this reduction occurs; Is it driven by primary production, via direct biologically mediated uptake, or alternatively is it driven chemically by redox reactions related to the passive release of reduced substances from the decay of biological materials? To directly address this question we have recently performed laboratory experiments and field measurements (Tropical Atlantic and Pacific, Southern Ocean) for this purpose. In culture experiments, including a variety of phytoplankton taxa (diatoms, dinoflagellates and prymnesiophytes), we observed changes in the speciation of iodine over the course of an experiment indicating the apparent ability to reduce iodate to iodide. Production rates were found to be species specific and not related to biomass. In all but one species tested the iodide production commenced in the stationary growth phase and peaked in the senescent phase of the algae. This indicates that iodide production is connected to cell senescence and suggests that iodate reduction results from increased cell permeability. We hypothesize that this is due to subsequent reactions of iodate with reduced sulphur species exuded from the cell. Combined with our field observations we suggest that cell senescence and other related processes that cause cell breakage (e.g. grazing, viral lysis) are responsible for the production of iodide. Our data additionally suggest that the iodine redox cycle is completed via biological processes also. We observed that an experimentally induced shift from senescence back to the exponential growth phase resulted in a decline in the iodide concentrations, suggesting reoxidation back to iodate. Our new data ... Conference Object Southern Ocean OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Pacific Southern Ocean |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
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The role of marine organisms in the redox cycling of iodine in the ocean is not well understood presently. Previous studies have suggested that phytoplankton play an important role in the biogeochemical cycling of iodine, and were responsible for the appearance of the non thermodynamically favoured species iodide in the euphotic zone. A key question that arises however is how this reduction occurs; Is it driven by primary production, via direct biologically mediated uptake, or alternatively is it driven chemically by redox reactions related to the passive release of reduced substances from the decay of biological materials? To directly address this question we have recently performed laboratory experiments and field measurements (Tropical Atlantic and Pacific, Southern Ocean) for this purpose. In culture experiments, including a variety of phytoplankton taxa (diatoms, dinoflagellates and prymnesiophytes), we observed changes in the speciation of iodine over the course of an experiment indicating the apparent ability to reduce iodate to iodide. Production rates were found to be species specific and not related to biomass. In all but one species tested the iodide production commenced in the stationary growth phase and peaked in the senescent phase of the algae. This indicates that iodide production is connected to cell senescence and suggests that iodate reduction results from increased cell permeability. We hypothesize that this is due to subsequent reactions of iodate with reduced sulphur species exuded from the cell. Combined with our field observations we suggest that cell senescence and other related processes that cause cell breakage (e.g. grazing, viral lysis) are responsible for the production of iodide. Our data additionally suggest that the iodine redox cycle is completed via biological processes also. We observed that an experimentally induced shift from senescence back to the exponential growth phase resulted in a decline in the iodide concentrations, suggesting reoxidation back to iodate. Our new data ... |
format |
Conference Object |
author |
Bluhm, Katrin Croot, Peter Wuttig, Kathrin Lochte, Karin |
spellingShingle |
Bluhm, Katrin Croot, Peter Wuttig, Kathrin Lochte, Karin Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton |
author_facet |
Bluhm, Katrin Croot, Peter Wuttig, Kathrin Lochte, Karin |
author_sort |
Bluhm, Katrin |
title |
Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton |
title_short |
Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton |
title_full |
Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton |
title_fullStr |
Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton |
title_full_unstemmed |
Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton |
title_sort |
cell permeability/senescence controls the reduction rate of iodate to iodide in marine phytoplankton |
publishDate |
2011 |
url |
https://oceanrep.geomar.de/id/eprint/12452/ |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Bluhm, K., Croot, P., Wuttig, K. and Lochte, K. (2011) Cell Permeability/Senescence Controls the Reduction Rate of Iodate to Iodide in Marine Phytoplankton. [Talk] In: Goldschmidt Conference 2011. , 14.-19.08.2011, Prague, Czech Republic . |
_version_ |
1766207558904709120 |