Ocean acidification reduces iodide production by the marine diatom Chaetoceros sp. (CCMP 1690)
Ocean acidification reduces iodide production by the marine diatom Chaetoceros sp. (CCMP 1690)
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DOI：
10.1016/j.marchem.2023.104311
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发表时间：
2023-09
期刊：
影响因子：
3
通讯作者：
Ergün Bey;Ciaran Hughes;Karen Hogg;Rosie Chance;Katherina Petrou
中科院分区：
文献类型：
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作者：
Ergün Bey;Ciaran Hughes;Karen Hogg;Rosie Chance;Katherina Petrou
海洋表层水中的浮游植物在全球碘循环中发挥着关键作用。未来情景下生物介导的碘化物生产是有限的。在这里，我们比较了硅藻 Chaetocerossp 的生长、碘酸盐到碘化物的转化率和膜渗透性。 (CCMP 1690) 在海水碳酸盐化学条件下生长，预计浓度为 2100 (1000 ppm) 和工业化前 (280 ppm) 条件。我们发现二氧化碳对生长速率没有影响，但在高二氧化碳下细胞产量显着提高，这表明由于碳限制的缓解而持续生长。在高 pCO2 条件下生长的培养物中，细胞归一化的碘酸盐摄取量 (16.73 ± 0.92 amol IO3−cell−1) 和碘化物产量 (8.61 ± 0.15 amol I−cell−1) 低于暴露于工业化前条件下的培养物 (21.29 ± 2.37 amol IO3−cell−1、11.91 ± 1.49 amol)分别为 I−cell−1)。将这些测量值与膜渗透性相关联，我们能够确定碘化物转化率与细胞渗透性无关，并且介导的碘酸盐损失和硅藻碘化物形成的过程是解耦的。这些发现首次表明 OA 可能驱动硅藻介导的碘酸盐还原的潜在转变。如果我们的结果表明 2100 年存在硅藻介导的碘循环，那么未来的表面海洋条件可能会经历毛藻类产生碘化物的速率降低，从而可能降低该类群主导的海洋区域的碘化物浓度。这些变化有可能影响大气中的臭氧循环和新颗粒的形成。
Phytoplankton in marine surface waters play a key role in the global iodine cycle. The biologically-mediated iodide production under future scenarios is limited. Here we compare growth, iodate to iodide conversion rate and membrane permeability in the diatomChaetocerossp. (CCMP 1690) grown under seawater carbonate chemistry conditions projected for 2100 (1000 ppm) and pre-industrial (280 ppm) conditions. We found no effect of CO2on growth rates, but a significantly higher cell yield under high CO2, suggesting sustained growth from relief from carbon limitation. Cell normalised iodate uptake (16.73 ± 0.92 amol IO3−cell−1) and iodide production (8.61 ± 0.15 amol I−cell−1) was lower in cultures grown at high pCO2than those exposed to pre-industrial conditions (21.29 ± 2.37 amol IO3−cell−1, 11.91 ± 1.49 amol I−cell−1, respectively). Correlating these measurements with membrane permeability, we were able to ascertain that iodide conversion rates were not linked to cell permeability and that the processes of mediated iodate loss and diatom-iodide formation are decoupled. These findings are the first to implicate OA in driving a potential shift in diatom-mediated iodate reduction. If our results are indicative of diatom-mediated iodine cycling in 2100, future surface ocean conditions could experience reduced rates of iodide production byChaetocerosspp., potentially lowering iodide concentrations in ocean regions dominated by this group. These changes have the potential to impact ozone cycling and new particle formation in the atmosphere.