Kirsten P. Fentzke, Andrew P. Rees, Glen A. Tarran, Sarah A. Breimann, Jerzy Blusztajn, Sune G. Nielsen, Dalton S. Hardisty
{"title":"沿大西洋经向带的真光碘酸盐生产","authors":"Kirsten P. Fentzke, Andrew P. Rees, Glen A. Tarran, Sarah A. Breimann, Jerzy Blusztajn, Sune G. Nielsen, Dalton S. Hardisty","doi":"10.1016/j.chemgeo.2025.122988","DOIUrl":null,"url":null,"abstract":"The oxidized iodine species, iodate, is abundant in well‑oxygenated marine waters and can be tracked in sediments to reconstruct ancient oxygen availability. Despite known modern marine spatial variations in both iodate and reduced iodide, the rates, pathways, and locations of iodate formation remain poorly understood for temporal gradients across Earth history. To quantify rates and pathways of iodate formation across an ocean basin, we performed ship-board tracer experiments in euphotic waters with known gradients in iodine speciation on an Atlantic Meridional Transect (45°S and 37°N). We performed incubations at depths corresponding to 7 % and 1 % of ambient surface light levels, thus tracking the boundaries of the deep chlorophyl maximum (DCM), from 11 stations along the transect. All incubations were spiked with a <ce:sup loc=\"post\">129</ce:sup>I (t<ce:inf loc=\"post\">1/2</ce:inf>≈15.7 My) tracer and mimicked ambient conditions. We observed iodate production via multiple pathways. The most common observation was a lack of significant iodate production, with iodate production limited to 7 of the 22 locations and nearly exclusively observed at the DCM and outside the nitrogen and iron limited South Atlantic Gyre. Iodate formation from direct iodide oxidation is inferred in only two locations based on increases in iodate <ce:sup loc=\"post\">129</ce:sup>I/<ce:sup loc=\"post\">127</ce:sup>I ratios. At the other locations, decreases in iodate <ce:sup loc=\"post\">129</ce:sup>I/<ce:sup loc=\"post\">127</ce:sup>I ratios imply that rapid reactions with and overturning of alternative natural iodine pools, likely iodine intermediates, are an important factor for iodate production. Our work emphasizes that the rates and pathways of iodate production are spatially heterogenous in the Atlantic Ocean. Future work is needed to determine the drivers, temporal variations, and trends within global ocean basins.","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"23 1","pages":"122988"},"PeriodicalIF":3.6000,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Euphotic iodate production along an Atlantic Meridional Transect\",\"authors\":\"Kirsten P. Fentzke, Andrew P. Rees, Glen A. Tarran, Sarah A. Breimann, Jerzy Blusztajn, Sune G. Nielsen, Dalton S. Hardisty\",\"doi\":\"10.1016/j.chemgeo.2025.122988\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The oxidized iodine species, iodate, is abundant in well‑oxygenated marine waters and can be tracked in sediments to reconstruct ancient oxygen availability. Despite known modern marine spatial variations in both iodate and reduced iodide, the rates, pathways, and locations of iodate formation remain poorly understood for temporal gradients across Earth history. To quantify rates and pathways of iodate formation across an ocean basin, we performed ship-board tracer experiments in euphotic waters with known gradients in iodine speciation on an Atlantic Meridional Transect (45°S and 37°N). We performed incubations at depths corresponding to 7 % and 1 % of ambient surface light levels, thus tracking the boundaries of the deep chlorophyl maximum (DCM), from 11 stations along the transect. All incubations were spiked with a <ce:sup loc=\\\"post\\\">129</ce:sup>I (t<ce:inf loc=\\\"post\\\">1/2</ce:inf>≈15.7 My) tracer and mimicked ambient conditions. We observed iodate production via multiple pathways. The most common observation was a lack of significant iodate production, with iodate production limited to 7 of the 22 locations and nearly exclusively observed at the DCM and outside the nitrogen and iron limited South Atlantic Gyre. Iodate formation from direct iodide oxidation is inferred in only two locations based on increases in iodate <ce:sup loc=\\\"post\\\">129</ce:sup>I/<ce:sup loc=\\\"post\\\">127</ce:sup>I ratios. At the other locations, decreases in iodate <ce:sup loc=\\\"post\\\">129</ce:sup>I/<ce:sup loc=\\\"post\\\">127</ce:sup>I ratios imply that rapid reactions with and overturning of alternative natural iodine pools, likely iodine intermediates, are an important factor for iodate production. Our work emphasizes that the rates and pathways of iodate production are spatially heterogenous in the Atlantic Ocean. Future work is needed to determine the drivers, temporal variations, and trends within global ocean basins.\",\"PeriodicalId\":9847,\"journal\":{\"name\":\"Chemical Geology\",\"volume\":\"23 1\",\"pages\":\"122988\"},\"PeriodicalIF\":3.6000,\"publicationDate\":\"2025-07-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Chemical Geology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1016/j.chemgeo.2025.122988\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Geology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1016/j.chemgeo.2025.122988","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Euphotic iodate production along an Atlantic Meridional Transect
The oxidized iodine species, iodate, is abundant in well‑oxygenated marine waters and can be tracked in sediments to reconstruct ancient oxygen availability. Despite known modern marine spatial variations in both iodate and reduced iodide, the rates, pathways, and locations of iodate formation remain poorly understood for temporal gradients across Earth history. To quantify rates and pathways of iodate formation across an ocean basin, we performed ship-board tracer experiments in euphotic waters with known gradients in iodine speciation on an Atlantic Meridional Transect (45°S and 37°N). We performed incubations at depths corresponding to 7 % and 1 % of ambient surface light levels, thus tracking the boundaries of the deep chlorophyl maximum (DCM), from 11 stations along the transect. All incubations were spiked with a 129I (t1/2≈15.7 My) tracer and mimicked ambient conditions. We observed iodate production via multiple pathways. The most common observation was a lack of significant iodate production, with iodate production limited to 7 of the 22 locations and nearly exclusively observed at the DCM and outside the nitrogen and iron limited South Atlantic Gyre. Iodate formation from direct iodide oxidation is inferred in only two locations based on increases in iodate 129I/127I ratios. At the other locations, decreases in iodate 129I/127I ratios imply that rapid reactions with and overturning of alternative natural iodine pools, likely iodine intermediates, are an important factor for iodate production. Our work emphasizes that the rates and pathways of iodate production are spatially heterogenous in the Atlantic Ocean. Future work is needed to determine the drivers, temporal variations, and trends within global ocean basins.
期刊介绍:
Chemical Geology is an international journal that publishes original research papers on isotopic and elemental geochemistry, geochronology and cosmochemistry.
The Journal focuses on chemical processes in igneous, metamorphic, and sedimentary petrology, low- and high-temperature aqueous solutions, biogeochemistry, the environment and cosmochemistry.
Papers that are field, experimentally, or computationally based are appropriate if they are of broad international interest. The Journal generally does not publish papers that are primarily of regional or local interest, or which are primarily focused on remediation and applied geochemistry.
The Journal also welcomes innovative papers dealing with significant analytical advances that are of wide interest in the community and extend significantly beyond the scope of what would be included in the methods section of a standard research paper.