Volatile organic iodine compounds (VOIs) emitted from the ocean surface to the air play an important role in atmospheric chemistry. Shipboard observations were conducted in Funka Bay, Hokkaido, Japan, bimonthly or monthly from March 2012 to December 2014, to elucidate the seasonal variations of VOI concentrations in seawater and their sea-to-air iodine fluxes. The bay water exchanges with the open ocean water of the North Pacific twice a year (early spring and autumn). Vertical profiles of CH2I2, CH2ClI, CH3I, and C2H5I concentrations in the bay water were measured bimonthly or monthly within an identified water mass. The VOI concentrations began to increase after early April at the end of the diatom spring bloom, and represented substantial peaks in June or July. The temporal variation of the C2H5I profile, which showed a distinct peak in the bottom layer from April to July, was similar to the PO43− variation profile. Correlation between C2H5I and PO43− concentrations (r = 0.93) suggests that C2H5I production was associated with degradation of organic matter deposited on the bottom after the spring bloom. CH2I2 and CH2ClI concentrations increased substantially in the surface and subsurface layers (0–60 m) in June or July resulted in a clear seasonal variation of the sea-to-air iodine flux of the VOIs (high in summer or autumn and low in spring).

中文翻译：

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日本北海道丰卡湾水体挥发性有机碘化合物的季节变化

从海洋表面排放到空气中的挥发性有机碘化合物 (VOI) 在大气化学中起着重要作用。2012 年 3 月至 2014 年 12 月，在日本北海道 Funka 湾进行了双月或每月的船上观测，以阐明海水中 VOI 浓度的季节性变化及其海-空碘通量。湾水每年与北太平洋的开阔海水交换两次（早春和秋季）。海湾水中 CH2I2、CH2ClI、CH3I 和 C2H5I 浓度的垂直分布在确定的水体中每两个月或每月测量一次。VOI 浓度在 4 月初硅藻春季开花结束后开始增加，并在 6 月或 7 月达到峰值。C2H5I 剖面的时间变化，4 月至 7 月在底层显示出明显的峰值，与 PO43− 变化剖面相似。C2H5I 和 PO43− 浓度之间的相关性 (r = 0.93) 表明 C2H5I 的产生与春季开花后沉积在底部的有机物的降解有关。6 月或 7 月地表和次表层（0-60 m）的 CH2I2 和 CH2ClI 浓度显着增加，导致 VOI 海气碘通量的明显季节性变化（夏秋季高，春季低） ）。