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Ocean acidification increases iodine accumulation in kelp-based coastal food webs


Xu, D and Brennan, G and Xu, L and Zhang, XW and Fan, X and Han, WT and Mock, T and McMinn, A and Hutchins, DA and Ye, N, Ocean acidification increases iodine accumulation in kelp-based coastal food webs, Global Change Biology, 25, (2) pp. 629-639. ISSN 1354-1013 (2018) [Refereed Article]

Copyright Statement

Copyright 2018 John Wiley & Sons Ltd.

DOI: doi:10.1111/gcb.14467


Kelp are main iodine accumulators in the ocean, and their growth and photosynthesis are likely to benefit from elevated seawater CO2 levels due to ocean acidification. However, there are currently no data on the effects of ocean acidification on iodine metabolism in kelp. As key primary producers in coastal ecosystems worldwide, any change in their iodine metabolism caused by climate change will potentially have important consequences for global geochemical cycles of iodine, including iodine levels of coastal food webs that underpin the nutrition of billions of humans around the world. Here, we found that elevated pCO2 enhanced growth and increased iodine accumulation not only in the model kelp Saccharina japonica using both short‐term laboratory experiment and long‐term in situ mesocosms, but also in several other edible and ecologically significant seaweeds using long‐term in situ mesocosms. Transcriptomic and proteomic analysis of S. japonica revealed that most vanadium‐dependent haloperoxidase genes involved in iodine efflux during oxidative stress are down‐regulated under increasing pCO2, suggesting that ocean acidification alleviates oxidative stress in kelp, which might contribute to their enhanced growth. When consumed by abalone (Haliotis discus), elevated iodine concentrations in S. japonica caused increased iodine accumulation in abalone, accompanied by reduced synthesis of thyroid hormones. Thus, our results suggest that kelp will benefit from ocean acidification by a reduction in environmental stress however; iodine levels, in kelp‐based coastal food webs will increase, with potential impacts on biogeochemical cycles of iodine in coastal ecosystems.

Item Details

Item Type:Refereed Article
Keywords:iodine, kelp, iodine metabolism, ocean acidification, Saccharina japonica, thyroid hormone, vanadium-dependent haloperoxidase
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Adaptation to climate change
Objective Field:Ecosystem adaptation to climate change
UTAS Author:McMinn, A (Professor Andrew McMinn)
ID Code:129493
Year Published:2018
Web of Science® Times Cited:18
Deposited By:Ecology and Biodiversity
Deposited On:2018-12-03
Last Modified:2019-03-15

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