Observational evidence for the formation of DMS-derived aerosols during Arctic phytoplankton blooms

Abstract

Abstract. The connection between marine biogenic dimethyl sulfide (DMS) and the formation of aerosol particles in the Arctic atmosphere was evaluated by analyzing atmospheric DMS mixing ratio, aerosol particle size distribution and aerosol chemical composition data that were concurrently collected at Ny-Ålesund, Svalbard (78.5 • N, 11.8 • E), during April and May 2015. Measurements of aerosol sulfur (S) compounds showed distinct patterns during periods of Arctic haze (April) and phytoplankton blooms (May). Specifically, during the phytoplankton bloom period the contribution of DMS-derived SO 2− 4 to the total aerosol SO 2− 4 increased by 7-fold compared with that during the proceeding Arctic haze period, and accounted for up to 70 % of fine SO 2− 4 particles (< 2.5 µm in diameter). The results also showed that the formation of submicron SO 2− 4 aerosols was significantly associated with an increase in the atmospheric DMS mixing ratio. More importantly, two independent estimates of the formation of DMS-derived SO 2− 4 aerosols, calculated using the stable S-isotope ratio and the non-seasalt SO 2− 4 / methanesulfonic acid ratio, respectively, were in close agreement, providing compelling evidence that the contribution of biogenic DMS to the formation of aerosol particles was substantial during the Arctic phytoplankton bloom period.

Processes Controlling the Composition and Abundance of Arctic Aerosol

“…Oceanic emissions of DMS are a large contributor to sulfur globally (Gondwe et al, ; Lana et al, ) and in Arctic regions (e.g., Becagli et al, ; Jarníková et al, ; Levasseur, ; Mungall et al, ; Park et al, , ). DMS results from bacterial breakdown of dimethylsulfoniopropionate, which is produced by marine phytoplankton and microalgae (e.g., Carpenter et al, ).…”

“…Long‐term observations at ground‐based monitoring stations demonstrate a relationship between the frequency of new particle formation events and oxidation products of DMS (Figure ), suggesting an important role for DMS in driving summertime particle formation (e.g., Dall'Osto et al, ; Leaitch et al, ; Park et al, , ). Uncertainties in the rates and mechanisms of nucleation by sulfuric acid, and subsequent growth, are such that some studies are able to explain ambient observations with standard parametrizations developed from measurements at mid‐latitudes (e.g., Chang, Sjostedt, et al, ), while others must invoke alternative mechanisms such as fragmentation of marine microgels (e.g., Karl et al, ).…”

“…Uncertainties in the rates and mechanisms of nucleation by sulfuric acid, and subsequent growth, are such that some studies are able to explain ambient observations with standard parametrizations developed from measurements at mid‐latitudes (e.g., Chang, Sjostedt, et al, ), while others must invoke alternative mechanisms such as fragmentation of marine microgels (e.g., Karl et al, ). Sulfur precursors to particle formation are often not well quantified in Arctic regions (Ghahremaninezhad et al, ; Giamarelou et al, ; Mungall et al, ; Park et al, ). Concentrations of sulfur dioxide are frequently low (i.e., <1 ppb v ) and conventional spectroscopic methods do not provide adequate sensitivity, hampering assessment of the general importance of sulfur species for Arctic particle formation.…”

Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

“…In the oligotrophic BATS station, some modeling studies proposed macronutrient limitation of bacteria (Polimene et al, 2011) and also phytoplankton (Belviso et al, 2012) as drivers of the seasonal mismatch between DMSPt and DMS, besides irradiance (Vallina et al, 2008). With this in mind, we tried to factor phosphate and nitrate limitation into our re-gression models using different variables: nutrient concentrations, nutricline depths (Table S4) and limitation factors estimated according to Michaelis-Menten kinetics (not shown).…”

“…Nevertheless, atmospheric studies powered by new analytical techniques (Kulmala et al, 2014) and modeling have shown instances where marine DMS controls ultrafine aerosol particle formation in the Arctic (Leaitch et al, 2013;Park et al, 2017), temperate North Atlantic (Sanchez et al, 2018), Antarctica (Yu and Luo, 2010) and the tropical South Pacific atmospheres (Modini et al, 2009). Moreover, Quinn et al (2017) recently reported that DMS-derived aerosols dominate cloud condensation nuclei populations over most of the global ocean.…”