Wintertime Arctic Sea Spray Aerosol Composition Controlled by Sea Ice Lead Microbiology
Wintertime Arctic Sea Spray Aerosol Composition Controlled by Sea Ice Lead Microbiology
复制标题
DOI：
10.1021/acscentsci.9b00541
复制
发表时间：
2019-11-27
影响因子：
18.2
通讯作者：
Pratt, Kerri A.
中科院分区：
文献类型：
--
作者：
Kirpes, Rachel M.;Bonanno, Daniel;Pratt, Kerri A.
北极正在经历地球上最严重的变暖，最明显的是海冰的迅速消失。阿拉斯加北极地区的海冰冻结延迟正在减少冬季海冰范围，并改变海洋生物活动。然而，新开放水域对冬季海雾气溶胶（SSA）产生和大气成分的影响尚不清楚。在此，我们确定了阿拉斯加北极沿海地区冬季由开放海冰裂缝（铅）产生的SSA是主要的气溶胶源，突出了北极SSA排放的全年性质。几乎所有单独的SSA都有厚厚的有机涂层，由海洋糖、氨基酸、脂肪酸和二价阳离子组成，与海冰藻类和细菌作为冷冻保护剂产生的外聚合物分泌物一致。相比之下，当地的夏季SSA缺乏这些有机碳涂层，或者具有薄涂层，附近只有开阔的水域。单个SSA的组成与海冰上的霜花或表面雪不一致，表明观测到的SSA既不是假设的霜花雾化造成的，也不是吹雪升华造成的。这些结果进一步证明了在北极大气成分模拟中纳入铅基SSA生产的必要性。已确定的海冰变化、微生物学和SSA之间的联系表明，海冰铅生物地球化学在改变北极冬季大气成分、云和气候反馈方面具有重要意义。
The Arctic is experiencing the greatest warming on Earth, as most evident by rapid sea ice loss. Delayed sea ice freeze-up in the Alaskan Arctic is decreasing wintertime sea ice extent and changing marine biological activity. However, the impacts of newly open water on wintertime sea spray aerosol (SSA) production and atmospheric composition are unknown. Herein, we identify SSA, produced locally from open sea ice fractures (leads), as the dominant aerosol source in the coastal Alaskan Arctic during winter, highlighting the year-round nature of Arctic SSA emissions. Nearly all of the individual SSA featured thick organic coatings, consisting of marine saccharides, amino acids, fatty acids, and divalent cations, consistent with exopolymeric secretions produced as cryoprotectants by sea ice algae and bacteria. In contrast, local summertime SSA lacked these organic carbon coatings, or featured thin coatings, with only open water nearby. The individual SSA composition was not consistent with frost flowers or surface snow above sea ice, suggesting that neither hypothesized frost flower aerosolization nor blowing snow sublimation resulted in the observed SSA. These results further demonstrate the need for inclusion of lead-based SSA production in modeling of Arctic atmospheric composition. The identified connections between changing sea ice, microbiology, and SSA point to the significance of sea ice lead biogeochemistry in altering Arctic atmospheric composition, clouds, and climate feedbacks during winter.