西太平洋海域现场培养实验中挥发性卤代烃浓度的变化及其影响因素

Variation of volatile halocarbons concentrations and its influencing factors in incubation experiments in the western Pacific Ocean

CH3I、CHCl3、C2HCl3和CH2Br2是挥发性卤代烃4种重要成分,对大气化学产生重要影响。于2018年10月在西太平洋进行船基现场培养实验,研究微量元素Fe (50 nmol/L)、酸化(pH=7.9)、酸化(pH=7.9)和微量元素Fe (50 nmol/L)耦合作用、微量元素Fe (50 nmol/L)和N/P (16∶1)耦合作用及沙尘(4 mg/L)对浮游植物释放CH3I、CHCl3、C2HCl3和CH2Br2含量的影响。结果表明,与对照组相比,实验组CH3I、C2HCl3和CH2Br2的释放均被不同程度抑制;CHCl3的释放除添加沙尘时表现抑制作用外,其他条件下均为促进作用;实验组培养周期内叶绿素a浓度较高,而营养盐浓度变化规律不明显。总的来说,酸化和微量元素Fe可能是影响浮游植物释放挥发性卤代烃的重要限制因素,沙尘对促进浮游植物生长繁殖的影响更为显著。

CH3I, CHCl3, C2HCl3 and CH2Br2 are the four important components of volatile halocarbons, which have important influence on atmospheric chemistry. To study the effect of Fe, ocean acidification, coupling effect of ocean acidification and Fe, coupling effect of Fe and N/P(16∶1) and dust on the concentrations of CH3I, CHCl3,C2HCl3 and CH2Br2 released by phytoplankton, an onboard incubation experiments was performed at the western Pacific Ocean in October 2018. Compared with the blank control experiment, the results show that the releases of CH3I, C2HCl3 and CH2Br2 in the experimental groups are suppressed in some extent. While the release of CHCl3 is promoted except when the dust is added. The concentration of Chl a is relatively high but the changes in nutrients concentrations are not obviously unconspicuous. In conclusion, the ocean acidification and iron fertilization might be the two virtual factors for phytoplankton to release volatile halocarbons. Besides, the growth of phytoplankton is affected significantly by the dust.