Iodine is an essential element needed in trace amounts by living organisms to maintain health and proper physiological functions. Living organisms acquire iodine through their diet in most cases and iodine is made available through biogeochemical cycling of this element. Most of what is known regarding the biogeochemical cycling of iodine comes from studies of seawaters and the atmosphere. While marine systems are a major global source of iodine, they do not account for total global iodine production. This research will help explain how bacteria in soil and sediments also contribute to global iodine cycling by studying genes potentially associated with iodine modification and by using laboratory techniques that replicate how different bacteria in terrestrial environments may work together to accomplish modifications of iodine compounds. Additionally, the outcomes of this research will improve the ability to predict how well certain bacteria will be able to modify radioactive iodine compounds. This has implications for the health of numerous ecosystems and populations that are currently threatened by radioactive iodine contamination. This project is a collaboration between Howard University and Alabama A&M University researchers and students (both undergraduate and graduate), and scientists at Pacific Northwest National Laboratory. Outreach activities in association with this project include presentations on environmental science and research techniques, as well as tours of research labs for students at the Howard University Middle School for Mathematics and Science.
In assessing the activities of bacterial communities in biogeochemical cycling of iodine this project will: 1) use functional genomics and metagenomics approaches to identify bacterial genes that contribute to the iodine redox cycle, iodination of organic compounds and accumulation of iodine and 2) develop and characterize re-engineered ecosystems derived from multispecies biofilm-based in vitro models for intracommunity interactions to investigate the activities of these bacteria in enriched communities, in isolation and in engineered communities. The results of this project will reveal the diversity of terrestrial bacteria that contribute in a variety of ways to global cycling of iodine and the underlying mechanisms, including microbe-microbe interactions and, potentially, previously uncharacterized biochemical pathways that drive these processes. This study represents the first multi-target, molecular and culture-based investigation of iodine cycling at both single species and multispecies levels.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
