Iodine in abiotic and biotic environments

• Main Authors: H. L. Antonyak, N. E. Panas, O. I. Pershyn, A. I. Polishchuk, N. K. Hoyvanovych
• Format: Article
• Language: English
• Published: Львівський національний університет імені Івана Франка 2018-09-01
• Series: Біологічні студії
• Subjects: iodine; environment; ecosystems; biota; marine algae; thyroid hormones
• Online Access: http://publications.lnu.edu.ua/journals/index.php/biology/article/view/826
• ISSN: 1996-4536; 2311-0783

Iodine, a trace element belonging to halogens, is a natural component of the Earth’s environment. However, its distribution in the environmental compartments is uneven and highly variable. Iodine is scarce in soil-forming parent rocks, soils and continental waters, but it is more abundant in the marine environment and organic rich sedimentary rocks. Iodine is ubiquitous in the biosphere, being found in virtually all organisms, both eukaryotes and prokaryotes. In vertebrates, including humans, iodine is used primarily for synthesis of thyroid hormones involved in the regulation of cellular metabolism and a host of vital body functions. Inadequate iodine intake by humans leads to serious health problems due to thyroid dysfunction and insufficient formation of thyroid hormones (endemic goitre, neurological abnormalities, cognitive impairment, physical development disorders, etc.). Many other biota groups living in different habitats can efficiently concentrate this element by absorbing inorganic iodine species from abiotic environments with the formation of various iodine-containing organic substances. Some of these compo­unds can serve metabolic and signaling functions in producing organisms, while others, such as volatile halocarbons, are involved in the transfer of iodine from the marine and terrestrial environments to the atmosphere. Consequently, terrestrial, soil and aquatic organisms (including microbial populations) capable of accumulating, metabolizing and volatilizing iodine mediate the processes of its biotransformation in the environment and contribute to the global iodine cycle. Marine organisms (algae, invertebrates) are stron­ger bioconcentrators of iodine in comparison with terrestrial biota. Brown algae of the genus Laminaria are the most potent iodine accumulators among all living systems. This article describes the distribution of iodine in abiotic and biotic environments, and the involvement of biotic processes in the biogeochemical cycle of iodine.