Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan.
Sci Rep. 2020 Oct 12;10(1):17042. doi: 10.1038/s41598-020-73718-5.
Linking the amount of organic matter (OM) in sea spray aerosols (SSAs) to biological processes in ocean surface is essential for understanding marine aerosol formation and their potential to affect cloud formation. To date, chlorophyll (Chl) a concentration has been widely used as a surrogate for surface phytoplankton biomass or productivity to predict the relative abundance of OM in SSAs (OM). Here we show a new index to present OM using concentrations of Chl a and chlorophyllide (Chllide) a, which is a breakdown product of Chl a and has been used as a biomarker of senescent algal cells. The index was compared with submicrometer OM, based on surface seawater and aerosol samples obtained during the pre-bloom in the western subarctic Pacific. Our results showed that the OM was highly correlated with this unique index, suggesting that the OM was closely linked with senescent algal cells and/or cell lysis. Furthermore, the hygroscopicity parameters κ derived from water-extracted SSA samples implied a reduction in the SSA hygroscopicity with increasing senescent status of phytoplankton. The index can represent OM on a timescale of a day during the pre-bloom period, which should be further examined over different oceanic regions.
将海雾气溶胶（SSA）中的有机物（OM）含量与海洋表面的生物过程联系起来，对于理解海洋气溶胶的形成及其对云形成的潜在影响至关重要。迄今为止，叶绿素（Chl）a 浓度已被广泛用作海洋表面浮游植物生物量或生产力的替代物，以预测 SSA 中 OM 的相对丰度（OM）。在这里，我们展示了一个使用 Chl a 和叶绿素 a 分解产物（Chllide）a 浓度表示 OM 的新指数，Chllide a 已被用作衰老藻类细胞的生物标志物。该指数与基于在西北亚北极太平洋浮游植物大量繁殖前获得的海面海水和气溶胶样本的亚微米级 OM 进行了比较。我们的结果表明，OM 与该独特指数高度相关，表明 OM 与衰老的藻类细胞和/或细胞裂解密切相关。此外，从水提取的 SSA 样本得出的吸湿性参数 κ 表明，随着浮游植物衰老状态的增加，SSA 的吸湿性降低。该指数可以在浮游植物大量繁殖前的一天时间尺度上代表 OM，这应该在不同的海洋区域进行进一步研究。
