see attached

This manuscript describes measurements made over two summers of sulfur containing aerosols, atmospheric DMS mixing ratio, and seawater DMSP concentrations at the Mario Zucchelli Station in Terra Nova Bay, Antarctica. The authors link the aerosol types to biogenic DMS sea-to-air fluxes. The data from the two summers are compared and contrasted. The authors conclude that polynya close to the station is the most important for producing DMS and subsequent fresh aerosols. They also determine a branching ratio of DMS oxidation for freshly produced aerosols to be ~0.84 (older airmasses have a lower ratio). Biogenic particulate matter makes up an average of 17% (max of 56%) of PM10 measured at the station during the summer season. The article contains interesting and useful data, which are sparse, so it should definitely be published. It is generally well written and the techniques/analyses are robust. There are a few minor to moderate issues that should be addressed before publishing. One general comment is that there a number of minor English errors, so the article should be proofread again before submission.

Specific comments:

Lines 40-41 – DMSO is overlooked by the authors. The cycling of the three compounds (DMS/P/O) is fast and significant (e.g., Archer et al., 2001).

Lines 45-47 – Why did the authors pick these reactants and citations? There is a more complete description in the recent publication by Fung et al. (2022) that also includes O3 in the water and Cl in the atmosphere.

Paragraph starting on line 74 – This is not true. DMS gas exchange has more of a linear relationship with wind speed, as it is largely transported by interfacial exchange and is not as influenced by bubbles (i.e. whitecaps, Bell et al., 2017; Zavarsky et al., 2018) as other more insoluble gases. This is also true for lines 258-259 and 270-271. The discussed decrease in exchange around 10 m/s winds is not universal (Bell et al., 2013; 2015; Yang et al., 2016; Blomquist et al., 2017; Zavarsky et al., 2018). Also, the argument from lines 272-275 (and line 372) is tenuous, especially without DMS measurements, as DMS in the water is more important for the flux than the wind (Marandino et al., 2007).

Line 100 – Should this include other types of aerosol (e.g., primary organics)?

Line 115 – Why is the Hulswar et al. (2022) climatology referenced here, but everywhere in the introduction only the earlier Lana (and Kettle) climatology is referenced?

Figure 1 – Formatting is different for reporting the years: 2018/2019 vs 2019-2020; typo – the caption says: figure on top reports enlarged map but should say figure on bottom shows enlarged map

Section 2.4 – I think it was a big oversight to not measure DMS in the water. Why was it not done? DMS can be measured reliably after a few hours of storage.

Lines 239-240 – Did the authors see the recent work on new DMS oxidation products and pathways? Perhaps this factors in to the calculation? The work is also referenced in the Fung et al. (2022) paper.

Line 288 – Are there not more recent studies corroborating this? I think this citation can be used, but it is very old. There is a modelling study by Bock et al. (2021) that may also shed some light on this issue.

Lines 290-291 – I would tend to agree with this statement, but it really needs a chemical transport model and measurements of DMS in the ocean to corroborate.

Lines 292-294 – As the authors mention a bit below, the correlation between biomass and DMS is not reliable (e.g., summer paradox, Simo and Pedros-Alios, 1999). Again, I think not having DMS measurements in the water is a large oversight. In general, these statements are fine (not wrong), but this piece is missing.

Paragraph starting on line 298 (and elsewhere e.g., lines 364-367) – The use/analysis of the back trajectories and the reaction times seems too little (line 375 on) – were trajectories over the whole region check and compared with all data (measured/downloaded)? Please also see my comments to lines 403 on.

Figure 2 and surrounding text – it is well known that the relationship between DMSP and DMS (in the water) is not straightforward – not only phytoplankton type but also physiology is important (temperature, light levels, etc.). DMS should be measured when possible and DMSO would have been a helpful measurement. Also, it has been observed that there can be a mismatch between DMS water and atmospheric levels, which has to do with physics and chemistry in the atmosphere. Maybe these discussions can be used to point to what future measurements may help elucidate the connections (that were missing here).

Lines 381-382 – Are there physical explanations here (what is influencing this chemistry) that could be mechanistically helpful?

Figure 6 – What are the trajectory durations?                                                                                                                                             

Lines 403-420 – Why are the reaction/transport times only considered important sometimes (no. 1) and not at other times (no. 2)? Even with fresh DMS emissions there will be a reaction time and the DMS laden air masses will be transported away before the relevant products form.

Figure 8 – Are the two slopes related to any other metadata – timing, location, air mass origin?

Line 465 – What is meant by “…reliable…branch ratio.”?

References

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Bell, T. G., De Bruyn, W., Marandino, C. A., Miller, S. D., Law, C. S., Smith, M. J., & Saltzman, E. S. (2015). Dimethylsulfide gastransfer coefficients from algal blooms in the Southern Ocean.Atmospheric Chemistry and Physics,15(4), 1783–1794.https://doi.org/10.5194/acp-15-1783-2015

Bell, T. G., De Bruyn, W., Miller, S. D., Ward, B., Christensen, K. H., & Saltzman, E. S. (2013). Air-sea dimethylsulfide (DMS) gas transferin the North Atlantic: Evidence for limited interfacial gas exchange at high wind speed.Atmospheric Chemistry and Physics,13(21),11,073–11,087. https://doi.org/10.5194/acp-13-11073-2013

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Bock, J., Michou, M., Nabat, P., Abe, M., Mulcahy, J. P., Olivié, D. J. L., Schwinger, J., Suntharalingam, P., Tjiputra, J., van Hulten, M., Watanabe, M., Yool, A., and Séférian, R.: Evaluation of ocean dimethylsulfide concentration and emission in CMIP6 models, Biogeosciences, 18, 3823–3860, https://doi.org/10.5194/bg-18-3823-2021, 2021.

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Yang, M., Bell, T. G., Blomquist, B. W., Fairall, C. W., Brooks, I. M., & Nightingale, P. D. (2016). Air-sea transfer of gas phase controlledcompounds.IOP Conference Series: Earth and Environmental Science,35(1), 012011.

Zavarsky, A., Goddijn-Murphy, L.,Steinhoff, T., & Marandino, C. A. (2018).Bubble-mediated gas transferand gas transfer suppressionof DMS and CO2.Journal ofGeophysical Research: Atmo-spheres,123, 6624–6647.https://doi.org/10.1029/2017JD028071