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Title: Marine gas-phase sulfur emissions during an induced phytoplankton bloom
Abstract. The oxidation of dimethyl sulfide (DMS;CH3SCH3), emitted from the surface ocean, contributes to theformation of Aitken mode particles and their growth to cloud condensationnuclei (CCN) sizes in remote marine environments. It is not clear whetherother less commonly measured marine-derived, sulfur-containing gases sharesimilar dynamics to DMS and contribute to secondary marine aerosolformation. Here, we present measurements of gas-phase volatile organosulfurmolecules taken with a Vocus proton-transfer-reaction high-resolutiontime-of-flight mass spectrometer during a mesocosm phytoplankton bloomexperiment using coastal seawater. We show that DMS, methanethiol (MeSH;CH3SH), and benzothiazole (C7H5NS) account for on averageover 90 % of total gas-phase sulfur emissions, with non-DMS sulfur sourcesrepresenting 36.8 ± 7.7 % of sulfur emissions during the first 9 d of the experiment in the pre-bloom phase prior to major biologicalgrowth, before declining to 14.5 ± 6.0 % in the latter half of theexperiment when DMS dominates during the bloom and decay phases. The molarratio of DMS to MeSH during the pre-bloom phase (DMS : MeSH = 4.60 ± 0.93) was consistent with the range of previously calculated ambient DMS-to-MeSH sea-to-air flux ratios. As the experiment progressed, the DMS to MeSHemission ratio increased significantly, reaching 31.8 ± 18.7 duringthe bloom and decay. Measurements of dimethylsulfoniopropionate (DMSP),heterotrophic bacteria, and enzyme activity in the seawater suggest theDMS : MeSH ratio is a sensitive indicator of the bacterial sulfur more » demand andthe composition and magnitude of available sulfur sources in seawater. Theevolving DMS : MeSH ratio and the emission of a new aerosol precursor gas,benzothiazole, have important implications for secondary sulfate formationpathways in coastal marine environments. « less
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Award ID(s):
1801971
Publication Date:
NSF-PAR ID:
10329719
Journal Name:
Atmospheric Chemistry and Physics
Volume:
22
Issue:
2
Page Range or eLocation-ID:
1601 to 1613
ISSN:
1680-7324
Sponsoring Org:
National Science Foundation
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