Temporal variations in atmospheric hydrogen sulphide concentrations and its biosphere-atmosphere exchanges were studied in the World’s largest mangrove ecosystem, Sundarbans, India. The results were used to understand the possible contribution of H2S fluxes in the formation of atmospheric aerosol of different size classes (e.g. accumulation, nucleation and coarse mode). The mixing ratio of hydrogen sulphide (H2S) over the Sundarban mangrove atmosphere was found maximum during the post-monsoon season (October to January) with a mean value of 0.59 ± 0.02 ppb and the minimum during pre-monsoon (February to May) with a mean value of 0.26 ± 0.01 ppb. This forest acted as a perennial source of H2S and the sediment-air emission flux ranged between 1213 ± 276 μg S m−2 d−1(December) and 457 ± 114 μg S m−2 d−1 (August) with an annual mean of 768 ± 240 μg S m−2d−1. The total annual emissions of H2S from the Indian Sundarban were estimated to be 1.2 ± 0.6 Tg S. The accumulation mode of aerosols was found to be more enriched with non-sea salt sulfate with an average loading of 5.74 μg m−3 followed by the coarse mode (5.18 μg m−3) and nucleation mode (1.18 μg m−3). However, the relative contribution of Non-sea salt sulfate aerosol to total sulfate aerosol was highest in the nucleation mode (83%) followed by the accumulation (73%) and coarse mode (58%). Significant positive relations between H2S flux and different modes of NSS indicated the likely link between H2S, a dominant precursor for the non-sea salt sulfate, and non-sea sulfate aerosol particles. An increase in H2S emissions from the mangrove could result in an increase in enhanced NSS in aerosol and associated cloud albedo, and a decrease in the amount of incoming solar radiation reaching the Sundarban mangrove forest.

中文翻译：

---

印度 Sundarban 红树林上空的生物硫化氢排放和非海硫酸盐气溶胶

在印度孙德尔本斯的世界上最大的红树林生态系统中研究了大气硫化氢浓度的时间变化及其生物圈-大气交换。结果用于了解 H2S 通量在不同大小级别（例如积累、成核和粗模式）大气气溶胶形成中的可能贡献。发现 Sundarban 红树林大气中硫化氢 (H2S) 的混合比在季风后季节（10 月至 1 月）最大，平均值为 0.59 ± 0.02 ppb，在季风前（2 月至 5 月）期间最小，平均值为 0.26 ± 0.01 ppb。该森林是 H2S 的常年来源，沉积物-空气排放通量介于 1213 ± 276 μg S m-2 d-1（12 月）和 457 ± 114 μg S m-2 d-1（8 月）之间，每年768 ± 240 μg S m-2d-1 的平均值。印度 Sundarban 的 H2S 年总排放量估计为 1.2 ± 0.6 Tg S。发现气溶胶的积累模式更富含非海盐硫酸盐，平均负荷为 5.74 μg m-3，其次是粗模式 (5.18 μg m-3) 和成核模式 (1.18 μg m-3)。然而，非海盐硫酸盐气溶胶对总硫酸盐气溶胶的相对贡献在成核模式 (83%) 中最高，其次是积累 (73%) 和粗模式 (58%)。H2S 通量与 NSS 不同模式之间的显着正相关表明 H2S 之间可能存在联系，非海盐硫酸盐和非海硫酸盐气溶胶颗粒的主要前体。红树林中 H2S 排放量的增加可能导致气溶胶和相关云反照率中 NSS 的增加，以及到达 Sundarban 红树林的太阳辐射量减少。