Abstract. An integrated observation of aerosol aminiums was conducted in a coastal city (Shanghai) in eastern China, a nearby island (Huaniao Island), and over the Yellow Sea and East China Sea (YECS). Triethylaminium (TEAH+) was abundant over Shanghai but not detected over the island and the open seas, suggesting its predominantly terrestrial origin. By contrast, relatively high concentrations of dimethylaminium (DMAH+) and trimethylaminium + diethylaminium (TMDEAH+) were measured over the ocean sites, indicating the significant marine source contribution. Environmental factors, including boundary layer height (BLH), temperature, atmospheric oxidizing capacity and relative humidity, were found to be related to aminium concentrations. All the detected aminiums demonstrated the highest levels in winter in Shanghai, consistent with the lowest BLH and temperature in this season. Aminiums mainly existed in fine particles and showed a bimodal distribution, with two peaks at 0.18–0.32 µm and 0.56–1.0 µm, indicating that condensation and cloud processing were the main formation pathways for aminiums in analogy with NH4+ and non-sea-salt SO42- (nss-SO42-). Nonetheless, a unimodal distribution for aerosol aminiums was usually measured over the YECS or over Huaniao Island when influenced mainly by the marine air mass, which suggested that aminiums in marine aerosols may undergo different formation pathways from those on the land. Terrestrial anthropogenic sources and marine biogenic sources were both important contributors for DMAH+ and TMDEAH+, and the latter exhibited a significantly higher TMDEAH+ to DMAH+ ratio. By using the mass ratio of methanesulfonate (MSA) to nss-SO42- as an indicator of marine biogenic source, we estimated that marine biogenic source contributed to 26 %–31 % and 53 %–78 % of aerosol aminiums over Huaniao Island in the autumn of 2016 and summer of 2017, respectively. Due to the important role of atmospheric amines in new particle formation, the estimation results highlighted the importance of marine biogenic emission of amines on the eastern coast of China, especially in summer.

Marine biogenic sources contribute substantially to atmospheric gaseous and particulate components and exert significantly environmental and climatic effects (Carpenter et al., 2012;O'Dowd et al., 2004). Ocean organism-derived dimethyl sulfide (DMS) is the largest natural source of sulfur-containing gases emitted to the atmosphere (Watts, 2000), which can be oxidized and transformed into sulfate aerosols and thereby impact the cloud condensation nuclei (CCN) and downward radiation over the ocean (Barnes et al., 2006;Charlson et al., 1987). A part of DMS will be oxidized to form methanesulfonic acid/methanesulfonate (MSA) by both gaseous and aqueous phase reactions in the atmosphere (Barnes et al., 2006;Hoffmann et al., 2016). MSA is one of the most abundant secondary organic aerosol (SOA) components in marine environment, and its ratio to non-sea-salt SO 4 2− (nss-SO 4 2-) ranges from less than 10 −2 to near 1 (Bates

Atmospheric deposition brings both nutrients and toxic components to the surface ocean, resulting in important impacts on phytoplankton. Field and lab studies have been done on the iron (Fe) fertilization on marine phytoplankton. However, studies on other trace metals are limited. Both bioassay experiments and field observations have suggested that aerosols with high copper (Cu) concentrations can negatively affect the primary productivity and change phytoplankton community structure. Note that with increasing human activities and global environmental changes (e.g., ocean acidification, warming, deoxygenation, etc.), the input of aerosol Cu could exceed toxicity thresholds at certain times or in some sensitive oceanic regions. Here, we provide a comprehensive review on aerosol Cu and marine phytoplankton studies by summarizing (1) physiological effects and toxicity thresholds of Cu to various phytoplankton taxa, (2) interactions between Cu and other metals and major nutrients, and (3) global distribution of surface seawater Cu and atmospheric Cu. We suggest that studies on aerosols, seawater chemistry, and phytoplankton should be integrated for understanding the impacts of aerosol Cu on marine phytoplankton, and thereafter the air–sea interaction via biogeochemical processes.

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