Role of sea spray aerosol at the air–sea interface in transporting aromatic acids to the atmosphere

Song, Yaru; Li, Jianlong; Tsona Tchinda, Narcisse; Li, Kun; Du, Lin

doi:10.5194/acp-24-5847-2024

Articles | Volume 24, issue 10

https://doi.org/10.5194/acp-24-5847-2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-24-5847-2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 24, issue 10

Research article

|

23 May 2024

Research article |

| 23 May 2024

Role of sea spray aerosol at the air–sea interface in transporting aromatic acids to the atmosphere

Yaru Song, Jianlong Li, Narcisse Tsona Tchinda, Kun Li, and Lin Du

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Final revised paper (published on 23 May 2024)
Supplement to the final revised paper
Preprint (discussion started on 04 Oct 2023)
Supplement to the preprint

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2023-2011', Anonymous Referee #1, 10 Nov 2023
General comments
I find this manuscript well-written / well-referenced, scientifically interesting for the SSA community, and the experimental quality is good. I find it great that the authors try connect SSA experiments with functional group level chemistry.
I have some minor concerns, that should be easily to address. I would recommend publication with only minor revisions.
Specific comments
Real seawater composition. In line 94 you write that you sample and transport seawater to the SSA laboratory. Is it possible to get more details? Conditions at sampling site (is it a productive area?), temperature, duration of storage, volume, was it filtered? Was it sampled on the same or different days? What time of year? You can add this information to the SI or just expand Table S1.
Also I have had challenges when I sampled fresh real seawater, that the SSA properties (size and number) changed as a function of time in the SSA chamber (due to microbial activity, degassing) – I therefore sometimes prepared artificial seawater from just inorganic sea salts. Could the authors elaborate on how reproducible the experiments are? And would the authors expect the results being similar using artifical inorganic mixture?

Experimental Setup. Would be helpful for the reader if Figure S1 was updated to include schematics of the entire setup, e.g. add where the DLPI+ was connected (before or after dryer?), single particle sampler (TEM). The air flow rate into SSA chamber (Line 109). Why does the range span from 3 all the way to 50 L min^-1? Is it because you have different setups at different times during a single experiment? Could you elaborate more on this.

TEM details. I am missing details about TEM instrument and conditions. When you do TEM, wouldn’t the organic coating of SSA just vaporize in the vacuum? Also, wouldn’t the SSA and aromatic acids be more internally mixed, when use a plunging jet / real bubble bursting?

Techical comments
Line 58: add mass, so it reads main mass component
Line 61: “... disturbing ecological systems... “, sound funny. Maybe change to “further impacting” or “further interaction with”
Line 163: The k look wierd, should be k_SSAas in Sha et al, right? Also chemical symbols should be upright, not italic.
Line 202: Unit, Part s-1, would prefer just s^-1 or particles s^-1.
Line 207: what does increase in bubble bursting refer to? Is it foam stability or lifetime? Or smaller and more bubbles?
Line 260: change ball to sphere
Line 323: “lousy” is informal slang, change to “very poor” or just “poor” or “around and just below 1”.
Line 351: … plays a very important role… Tone down, add “might play”
Figure 1: Maybe same range on y-axis? Easier to compare across subplots. I am colorblind, do you need the colors? If you perfer using colors, then should be the same as in Figure 2.
Figure 2. I would change the colors. Yellow is difficult to see. Look at this website for inspiration: https://colorbrewer2.org/#type=diverging&scheme=BrBG&n=4
Figure 3. Seawater = Seawater only. And maybe add some errorbar estimation with respect to SSA production? Here color is okay, but that white shadow looks funny.
Figure 6: Maybe make different symbols and use one color? Feel free to ignore this comment.
Figure 7. The space between the bars are not the same. Also I would change colors (Feel free to igore this comment)
Citation: https://doi.org/10.5194/egusphere-2023-2011-RC1
- AC1: 'Reply on RC1', Yaru Song, 26 Dec 2023
  
  The reply is attached.
  
  Citation: https://doi.org/10.5194/egusphere-2023-2011-AC1
CC1:
'Comment on egusphere-2023-2011', Bojiang Su, 15 Nov 2023

Dear Authors, editor, and reviewers,
This manuscript presents insights into the interactions between sea spray aerosols (SSAs) and aromatic acids through a laboratory study. This is an interesting and valuable research. I have some constructive comments on this manuscript.
Specific comments:
Abstract and Introduction:
Line 11, what is the importance of aromatic acids with SSAs in affecting the global radiative balance? In the following section of Introduction (Lines 29-40), the authors had ambiguous presentation in relationship between SSAs, aromatic acids, and global radiative balance.
Lines 41-54: The authors introduced the current studies in seawater source of aromatic acids in this paragraph, that is, the majority is from esters released and biodegraded by algae and the remain is from anthropogenic emissions. Could aromatic acids be derived from precipitation? What are the major types and their proportions and concentrations of aromatic acids in seawater? It should correspond to aromatic acids the authors used in the experiments (lines 90-98, 2 Experiment Section). More detailed description and possible summary are needed.
Line 80 Sintered glass filter and wave breaking method can also produce artificial SSAs with different properties of flux, chemical composition, size distribution, and so on. The authors should clarify the relationship between methods (sintered glass filter, plunging jet, and wave breaking) and possible efficiency of aromatic acid transport within SSAs. That is, whether the plunging jet method can effectively reflect the “Role of sea spray aerosol at the air-sea interface in transporting aromatic acids to the atmosphere”?
Experimental Section
Lines 90-97 Why do authors chose these types of aromatic acids? It should be clarified.
Lines 93-94 The collection procedure of seawater is not clear (site, chemical composition of seawater, contamination control, storge conditions, filtration or not?) Detailed QA/QC description is needed.
Line 98: What is the mass concentration of typical aromatic acids in true seawater, which determines whether the concentration of aromatic acid used in the experiment (1 mM) is reasonable.
Line 135 Can this flow rate of 1 mL min^-1 for 1 h collect particles? If so, possible sampling artifacts should be considered. I think this flow rate is too small and cannot achieve/tune with DKL-2.
Results and discussion
Section 3.2.2 and Fig. 4
How quantitatively determine the thickness of organic coating of collected individual particles and what is the basis of the order? Can thickness of organic coating of selected individual particles represent the whole populations? Is there a statistic bias using only one typical TEM image?
Section 3.3
How many samples were used to calculate the enrichment factors of aromatic acids and cations (both in Figures 5 and 6)? It should be summarized as a new table. The authors performed size-resolved filter-based experiments, what is the level of enrichment factors of aromatic acids in different size?
The authors hypothesize that the binding effect of Ca²⁺ with aromatic acid is a reason for observed positive enrichment of aromatic acids. In fact, the positive calcium enrichment is also observed using artificial seawater without organic matters (Salter et al., 2016). Therefore, this hypothesis may need additional control experiments, for example, using pure NaCl solution with addition of aromatic acids, to excluded the effect of Ca²⁺.
Lines 313-326 I found a missing detail in authors evaluate the cation enrichments, that is, the detailed mass concentration ratio of cations to Na⁺, for example of Ca²⁺/Na⁺, in both seawater and aerosol samples is missing. I therefore suggest the authors supplement more details in mass concentration ratio of aromatic acids and cations in seawater and aerosol samples as a new table.
Minor comments:
Lines 57: Please clarify “a potential route”.
Lines 59-62: This sentence is hard to follow. What is that sea-salt included organic surfactants can thereby further disturbing ecological systems? The cited references also seem inappropriate.
Line 109 What is the air flow rate? It should be different in different experiment procedures.
Fig.3 It is hard to follow the differences in particle size, because these circles are almost identical.
Fig.4 It is hard to follow the colors of subplots A, B, and C. The color span between groups should be larger.
Reference
Salter, M. E., Hamacher-Barth, E., Leck, C., Werner, J., Johnson, C. M., Riipinen, I., Nilsson, E. D., and Zieger, P.: Calcium enrichment in sea spray aerosol particles, Geophys Res Lett, 43, 8277-8285, https://doi.org/10.1002/2016gl070275, 2016.

Citation: https://doi.org/10.5194/egusphere-2023-2011-CC1
- AC3: 'Reply on CC1', Yaru Song, 26 Dec 2023
  
  The reply is attached.
  
  Citation: https://doi.org/10.5194/egusphere-2023-2011-AC3
RC2:
'Comment on egusphere-2023-2011', Matthew Salter, 21 Nov 2023

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2011/egusphere-2023-2011-RC2-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2023-2011-RC2
- AC2: 'Reply on RC2', Yaru Song, 26 Dec 2023
  
  The reply is attached.
  
  Citation: https://doi.org/10.5194/egusphere-2023-2011-AC2

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

AR by Yaru Song on behalf of the Authors (26 Dec 2023) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (07 Jan 2024) by Paul Zieger

RR by Anonymous Referee #1 (08 Jan 2024)

RR by Anonymous Referee #3 (07 Feb 2024)

RR by Matthew Salter (09 Feb 2024)

Suggestions for revision or reasons for rejection

While the authors have tried to enhance their manuscript, in my assessment, the work still falls short of meeting the standards required for ACP. Numerous issues persist, including poorly written text, absence of critical information, and inadequately explained figures, making it impossible for readers to verify the authors' conclusions. Below are examples highlighting the manuscript's shortcomings:

1) Writing Quality:
The manuscript exhibits poor writing quality, hindering the comprehension of the authors' ideas. Despite the authors' likely investment in study design and high-quality data collection, the narrative fails to match the same level of quality. For instance, the first paragraph lacks definitive articles and has verb mismatches and subject-verb disagreements throughout. The same issues are repeated throughout the manuscript. Additionally, sentence structure issues, such as awkward phrasing and lack of coherence, persist throughout the manuscript. An example is the use of acronyms (SSA, CCN, and IN) without prior explanation, which hampers clarity.

2) Structural Improvements:
The overall structure of the writing requires significant improvement. Taking the first paragraph as an example, the complexity of the topic results in a dense paragraph that is challenging to digest. Scientific writing often benefits from a one-idea-per-paragraph approach. Breaking down this paragraph into smaller, focused sections could enhance readability without sacrificing the depth of information. For instance, dividing it into two paragraphs—one emphasising the impact of acids on the environment and humans, and the other focusing on their potential climate impacts—would improve overall clarity. This approach should be taken throughout the manuscript

3) Figure Presentation:
The presentation of figures, such as Figure 7, falls below the expected standard. Figures should ideally be standalone, conveying information without heavy reliance on captions. In this case, the significance of the colour bars is unclear from both the plot and the caption, indicating a need for improved figure design and clarity. Readers need to understand the visual elements independently to enhance the overall effectiveness of the figures.

In light of these issues, I regret to inform you that I cannot recommend the publication of this manuscript at this time. Addressing the highlighted concerns, particularly improving writing quality, enhancing structural organisation, and refining figure presentation, is crucial to meet what I view as the required standards for acceptance in ACP.

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ED: Reconsider after major revisions (09 Feb 2024) by Paul Zieger

AR by Yaru Song on behalf of the Authors (04 Mar 2024) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (10 Mar 2024) by Paul Zieger

RR by Anonymous Referee #3 (11 Mar 2024)

RR by Matthew Salter (25 Mar 2024)

ED: Publish subject to minor revisions (review by editor) (28 Mar 2024) by Paul Zieger

Dear authors,
Thank you very much for your revised version. The reviewers and I had another read. While the overall quality of the present manuscript has improved, there are still many technical and minor issues that need to be resolved before final publication. I strongly recommend another thorough editorial read to check for spelling and grammatical errors. I give a few examples but do not have the time to correct all of them. Please also consult the manuscript preparation guidelines (https://www.atmospheric-chemistry-and-physics.net/submission.html) and harmonize abbreviations and provide consistent/correct units. Further comments are given by the reviewers and myself below.

Kind regards

Paul Zieger.

Comments (line number refer to the latest version of the manuscript w/o track changes):
- Line 36: SSA should be explained here at its first occurrence and not in line 63.
- Line 36-40: There is some repetition here with respect to CCN.
- Line 99: Figure or Table S1?
- Line 124: Are the RH and T-ranges measured or technically given/fixed?
- Line 130: I would give the mean and standard deviation of the measured RH (since you measured it).
- Line 133: particles -> particle
- Line 136: Better “<20 cm-3” (remove the hashtag)
- Line 155: Add “a” before “muffle”
- Beginning of Sect. 3.1: This should be part of the methods and not the result section.
- Table 1 caption: add “the” before “experiments”
- Figure 1: Please describe properly the box plot. What are the whiskers showing? How many data points are included in each box? 3 points is not enough (as suggested in the caption).
- Figure 2: “SW” is not properly defined. Is it the ambient sea water or the artificial sea water (which in the text is abbreviated as ASW). Please make sure that all abbreviations are properly defined.
- Figure 3: Define “SW”. It is really hard to see difference in the circle size. In the caption, make clear that “numbers above the points give the geometric mean diameter (in nm)”. Errorbars are standard deviation?
- Figure 7: Harmonize if you use “tons” or “tonnes” within the figures and text.
- Supplement:
o All figures and tables in the SI need to be also referenced in the main text. I could not find S5, S9 and S10 in the main text! Otherwise remove them.
o Figure S5: Please increase font size and check the y-labels.
o Suggest to use normal page numbers and not S1, S2, etc. to not confuse with the figure and table labelling.
- Data availability: I strongly recommend to make the data publicly available and follow the data policy of ACP (https://www.atmospheric-chemistry-and-physics.net/policies/data_policy.html).

See also comments by reviewers 1 and 2.

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AR by Yaru Song on behalf of the Authors (06 Apr 2024) Author's response Author's tracked changes Manuscript

ED: Publish as is (11 Apr 2024) by Paul Zieger

AR by Yaru Song on behalf of the Authors (11 Apr 2024) Author's response Manuscript

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Short summary

Aromatic acids can be transferred from seawater to the atmosphere through bubble bursting. The air–sea transfer efficiency of aromatic acids was evaluated by simulating SSA generation with a plunging jet. As a whole, the transfer capacity of aromatic acids may depend on their functional groups and on the bridging effect of cations, as well as their concentration in seawater, as these factors influence the global emission flux of aromatic acids via SSA.