Iodine cycle

Biogeochemical iodine cycle: Inventories are in Tg iodine per year. Labeled flux arrows are in Gg iodine per year. Unlabeled inventories (sinks) and fluxes are of unknown quantities. Iodine cycles through the lithosphere, atmosphere, hydrosphere, and biosphere. [1][2][3][4] Freshwater iodine is calculated by subtracting oceanic iodine[4] from total iodine in the hydrosphere.[1] In oceans sediments and crust, iodine is replenished by sedimentation[1] and is cycled into seawater through release as brine during subduction.[4] Marine biota uptake iodine from seawater[1] where it may be volatilized by transformation to methyl iodide.[3] Sea spray aerosolization, volcanic activity, and fossil fuel burning cycles iodine from the hydrosphere and lithosphere into the atmosphere as well,[1] while wet[2] and dry deposition remove iodine from the atmosphere.[1] In soil, small quantities of iodine are cycled through weathering of parent rock.[1] Terrestrial biota uptake and remove iodine from soil, and bacteria volatilize iodine by methylizing it.[1]

The iodine cycle is a biogeochemical cycle that primarily consists of natural[1] and biological processes[3] that exchange iodine through the lithosphere, hydrosphere, and atmosphere.[3][2] Iodine exists in many forms, but in the environment, it generally has an oxidation state of -1, 0, or +5.[1]

  1. ^ a b c d e f g h i j Fuge, Ronald; Johnson, Christopher C. (1986). "The geochemistry of iodine — a review". Environmental Geochemistry and Health. 8 (2): 31–54. doi:10.1007/BF02311063. ISSN 1573-2983. PMID 24213950. S2CID 45457666.
  2. ^ a b c Whitehead, D. C. (1984). "The distribution and transformations of iodine in the environment". Environment International. 10 (4): 321–339. doi:10.1016/0160-4120(84)90139-9. ISSN 0160-4120.
  3. ^ a b c d Amachi, Seigo (2008). "Microbial Contribution to Global Iodine Cycling: Volatilization, Accumulation, Reduction, Oxidation, and Sorption of Iodine". Microbes and Environments. 23 (4): 269–276. doi:10.1264/jsme2.ME08548. ISSN 1342-6311. PMID 21558718.
  4. ^ a b c Muramatsu, Yasuyuki; Yoshida, Satoshi; Fehn, Udo; Amachi, Seigo; Ohmomo, Yoichiro (2004). "Studies with natural and anthropogenic iodine isotopes: iodine distribution and cycling in the global environment". Journal of Environmental Radioactivity. Papers from the International Conference on Radioactivity in the Environment, Monaco, 1-5 September 2002. 74 (1): 221–232. doi:10.1016/j.jenvrad.2004.01.011. ISSN 0265-931X. PMID 15063550.