Tracing the contribution of dust sources on deposition and phytoplankton carbon uptake in global oceans

Liu, Yaxin; Xiao, Yunting; Cui, Lehui; Guo, Qinghao; Sun, Yiyang; Fu, Pingqing; Liu, Cong-Qiang; Zhu, Jialei

doi:https://doi.org/10.5194/egusphere-2025-763

Preprints

https://doi.org/10.5194/egusphere-2025-763

Preprints

06 Mar 2025

| 06 Mar 2025

Tracing the contribution of dust sources on deposition and phytoplankton carbon uptake in global oceans

Yaxin Liu, Yunting Xiao, Lehui Cui, Qinghao Guo, Yiyang Sun, Pingqing Fu, Cong-Qiang Liu, and Jialei Zhu

Abstract. Dust provides iron essential for marine phytoplankton growth, altering their carbon uptake capacity and affecting the global carbon cycle. However, due to the limited availability of observational parameters applied in evaluation models, there remains uncertainty in the contribution of marine dust deposition to carbon uptake. Here, we quantified the separate contributions of eleven major dust sources to dust deposition and marine ecological response to dust-borne iron in eight ocean regions based on the series of simulations constrained by multiple global observation datasets of iron solubility and total iron concentration in the oceans as well as iron content in the dust. Our simulations indicate that dust deposition could supply 11.1 Tg yr^-1 of iron and 0.4 Tg yr^-1 of dissolved iron to the oceans, promoting 5.6 Pg C yr⁻¹ of carbon uptake by marine phytoplankton.

Received: 18 Feb 2025 – Discussion started: 06 Mar 2025

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.

Download & links

Preprint (PDF, 2425 KB)

Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
Preprint (2425 KB)

Supplement (3049 KB)

Download & links

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Journal article(s) based on this preprint

06 Nov 2025

Tracing the contribution of dust origins on deposition and phytoplankton carbon uptake in global oceans

Yaxin Liu, Yunting Xiao, Lehui Cui, Qinghao Guo, Yiyang Sun, Pingqing Fu, Cong-Qiang Liu, and Jialei Zhu

Biogeosciences, 22, 6445–6464, https://doi.org/10.5194/bg-22-6445-2025,https://doi.org/10.5194/bg-22-6445-2025, 2025

Short summary

Yaxin Liu, Yunting Xiao, Lehui Cui, Qinghao Guo, Yiyang Sun, Pingqing Fu, Cong-Qiang Liu, and Jialei Zhu

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-763', Anonymous Referee #1, 26 Mar 2025

I would like to acknowledge that the authors may not be native English speakers, and I appreciate their efforts to write in English. As a non-native speaker myself, I understand the challenges involved. Any comments I make regarding syntax or phrasing are solely intended to clarify the manuscript and are not meant to judge the authors' English writing abilities.

Review of “Tracing the contribution of dust sources on deposition and phytoplankton carbon uptake in global oceans” by Liu et al.

General comments:
The article presents modeling results of global iron emissions from natural dust simulated with an ESM (CLM). These simulations take into account various dust source regions, which lead to varying Fe solubility. This approach is original since most, if not all previous global studies of Fe dust deposition used a global average for Fe solubility in dust. These Fe dust estimates are then translated into dissolved Fe (dFe) fluxes at the surface ocean, and extrapolated as C uptake according to Equation 4.
The authors underline the importance of Fe deposition for surface ocean carbon cycling, in particular in HNLC areas such as the Southern Ocean.
The original idea of simulating Fe dust deposition while considering spatial variability in the sources is interesting and novel. Estimating the potential implications for carbon uptake by phytoplankton is also interesting. However, the authors maintain (maybe involuntarily) a huge confusion with carbon uptake estimates. As a result, it may seem like the authors are estimating total ocean carbon uptake (i.e. air-sea carbon fluxes). They even compare their results with such estimates in the discussion. But this is not what the authors are calculating in this study. What is estimated here, is phytoplankton uptake of carbon, driven by the Fe supply from natural dust. I want to trust that this confusion is not a voluntary one by the authors. However, this must be corrected before the article can be published.
The use of the term ‘carbon uptake’ leads to some confusion. It is stated in the abstract that the authors refer to “phytoplankton carbon uptake”. But later in the text, it is termed “marine carbon uptake” (e.g. lines, 101, 103, 110, 132, 271). A good definition of the term ‘carbon uptake’ is central to the understanding of this manuscript. I recommend the authors clarify the term throughout the manuscript and refer to “phytoplankton carbon uptake”. Marine carbon uptake is very different from phytoplankton carbon uptake. In this study, the authors quantify phytoplankton carbon uptake, and not marine carbon uptake (which is mostly driven by physical factors).
Abstract:
The authors claim that their results show that iron dust deposition promotes “5.6 Pg C yr⁻¹ of carbon uptake by marine phytoplankton.” This value should be compared with the global uptake estimated without iron dust. Is this additional uptake significant?
Introduction:
Lines 113-122: I’m not certain that the paragraph on satellite observation is necessary here.
Methods:
2.1. Community Earth System Model
Some details are lacking. What is the time step of the model for emissions and depositions? What is the spatial resolution of the model? How many vertical levels are represented in the model?
Did you run simulations? Which forcings did you use? Which environmental conditions?
In Equation 1, the different factors should be properly defined: how do you define the tuning factor? What values does it take? Give the values and units of all variables.

Line 193: Replace “marine carbon uptake” by “phytoplankton carbon uptake”. This sentence should be moved to section 2.5.

Paragraph lines 198-203: What’s the time resolution of you simulations?

Line 239: “The dFe concentration data is a necessary factor for calculating the Fe: C ratio in phytoplankton cells”.

2.5 Calculation of Carbon Uptake
This section lacks details and precision, from which stem a lot of confusion. Dfe is concentration data taken from the GEOTRACES database (according to section 2.3), but on line 280, it is described as “dFe is the local concentration of soluble Fe”. Soluble and dissolved Fe are different things.
The definition of FeOpt should be detailed: is it the optimal Fe concentration in the water or in phytoplankton cells?
Finally, in order to avoid any confusion, the Fe:C ratio should be referred to Fe:C ratio in phytoplankton cells.
Line 275: “ambient soluble Fe” should be replaced by “dissolved Fe in seawater”.
Line 276: marine carbon uptake should be replaced by phytoplankton carbon uptake
The units of each term in Equation 4 should be described.

Results:
The results are presented with great details. However, most figures could be reworked to be simplified and easier to read.
The paragraph and associated figures on wet/dry deposition may be removed since you don’t discuss these results. Maybe they can remain in supplement, but I don’t find these results central to the study.
Figure 1: the names of the regions are difficult to read
Figure 2: The pie charts are almost impossible to see on the figure. The percentage already appears, so, maybe they can be removed.
Figures 3 and 7 could be grouped in 1 figure with 2 panels.
Figure 4: remove the pie charts. Describe the percentages either in the text or in the legend.
Figure 7 and 8 are very interesting, but I do not understand what the longitudinal columns with percentages represent. Maybe this could be simplified.
Figure 8 can go in supplement.
Figure 9: Remove the pie charts and change the legend to indicate that this is phytoplankton carbon uptake.
Figure 10 can go in supplement
Figure 11: change the legend to indicate that this is phytoplankton carbon uptake.
Figure 11 and 12 could be merged into 1 figure with 2 panels.
Figure 13: I do not understand the longitudinal columns. They can be removed to simplify the figure. Correct the legend to “phytoplankton carbon uptake”.

Lines 425-433: there is a lot of information that has already been described in the Methods. Some sentences can be removed (e.g. lines 431-433). Here specifically, the authors introduce a lot of confusion by writing “marine carbon uptake” instead of “phytoplankton carbon uptake”. Please change all occurrences to “phytoplankton carbon uptake”.

Lines 436-445: This seems to be discussion more than results.
Lines 441-445: “We estimated the global marine carbon uptake associated with new growth resulting from dust deposition, using the Fe:C ratio, since, regardless of whether in HNLC or LNLC regions, phytoplankton can respond to dust deposition. However, Fe is not the sole primary limiting nutrient in LNLC regions; therefore, we also quantified the marine carbon uptake resulting from new growth driven by dust deposition exclusively in HNLC regions.”. I don’t understand these statements.
Later (lines 499-501) it is stated: “Since Fe is the most primary limiting factor in HNLC regions, we estimated the result of marine carbon uptake for new growth induced by dust deposition only over HNLC regions.” Did you or did you not look at LNLC regions and why?

Discussion:
The discussion lacks some quantitative comparison of the author’s results with previous works.
For instance, the authors found that the Equatorial Indian and Atlantic oceans receive most of the global dust, and this dust is coming from the main emission sources. How did the author’s work bring novelty to these observations?
As currently written, the discussion repeats the results instead of putting the study results into perspective.
Lines 613-620: The comparison of the results with Mahowald’s results is very confusing and I think, false. This study quantifies carbon uptake by phytoplankton, it is in no way a translation of total carbon uptake by the ocean. The difference between this study and Mahowald’s results does not just stem from different methods, but on different objectives. This entire paragraph of discussion should be removed as these are not comparable results.

Lines 643-646: “Moreover, ecological models, such as the BEC model, incorporate various potentially growth-limiting nutrients and have ability to simulate different phytoplankton functional groups, which could be compared to our evaluation.” In this study, only Fe is considered a limiting nutrient for phytoplankton. You could discuss the implications of this assumption since, as stated here, other nutrients may limit or co-limit phytoplankton growth and carbon uptake.
Lines 646-648: The comparison with Westberry is also complicated here, primary production and phytoplankton carbon uptake are not strictly similar processes and may not be directly comparable. The following discussion on satellite data seems unecessary to the article.
The comparison with CMIP6 data should be more clearly explicited. Which models did you use? What variables did you compare your results to? Do all CMIP models use a variable Fe:C ratio for phytoplankton? How does that affect your comparison? Which years of CMIP simulations did you use? Which scenario?

-----------------------------------------------------------

Minor comments:
Abstract line 30: “Dust provides iron, which is an essential for marine phytoplankton growth,”
Line 36: “...based on a series of simulations…”
Line 47: replace “carrying’ by “carries” and add “be” before “deposited”.
Line 101: Rephrase to avoid the repetition of “carbon uptake” and clarify that you are talking about phytoplankton carbon uptake.
Line 136-137: “Fe:C ratios in phytoplankton cells […] to estimate the global carbon uptake by phytoplankton”
Line 140: replace “marine carbon uptake” by “phytoplankton carbon uptake”.
Line 211: “Fe solubility is also a key factor to estimate the carbon uptake of ocean to dust deposition” replace carbon uptake of ocean, by “carbon uptake of phytoplankton”.
Line 239: “The dFe concentration data is a necessary factor for calculating the Fe: C ratio.” Do you mean the Fe:C ratio of phytoplankton?

Citation: https://doi.org/10.5194/egusphere-2025-763-RC1
- AC1: 'Reply on comments from two reviewers', Jialei Zhu, 24 Jun 2025
  
  Please see our response in the supplement.
  
  Citation: https://doi.org/10.5194/egusphere-2025-763-AC1
RC2:
'Comment on egusphere-2025-763', Joan Llort, 06 Jun 2025

The manuscript provides interesting and relevant new insights into the regional and seasonal distribution of dust emissions and deposition. However, the results on phytoplankton carbon uptake linked to dust are less convincing and require additional work to be accepted for publication. See the attached file for details.

Citation: https://doi.org/10.5194/egusphere-2025-763-RC2
- AC1: 'Reply on comments from two reviewers', Jialei Zhu, 24 Jun 2025
  
  Please see our response in the supplement.
  
  Citation: https://doi.org/10.5194/egusphere-2025-763-AC1

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-763', Anonymous Referee #1, 26 Mar 2025

I would like to acknowledge that the authors may not be native English speakers, and I appreciate their efforts to write in English. As a non-native speaker myself, I understand the challenges involved. Any comments I make regarding syntax or phrasing are solely intended to clarify the manuscript and are not meant to judge the authors' English writing abilities.

Review of “Tracing the contribution of dust sources on deposition and phytoplankton carbon uptake in global oceans” by Liu et al.

General comments:
The article presents modeling results of global iron emissions from natural dust simulated with an ESM (CLM). These simulations take into account various dust source regions, which lead to varying Fe solubility. This approach is original since most, if not all previous global studies of Fe dust deposition used a global average for Fe solubility in dust. These Fe dust estimates are then translated into dissolved Fe (dFe) fluxes at the surface ocean, and extrapolated as C uptake according to Equation 4.
The authors underline the importance of Fe deposition for surface ocean carbon cycling, in particular in HNLC areas such as the Southern Ocean.
The original idea of simulating Fe dust deposition while considering spatial variability in the sources is interesting and novel. Estimating the potential implications for carbon uptake by phytoplankton is also interesting. However, the authors maintain (maybe involuntarily) a huge confusion with carbon uptake estimates. As a result, it may seem like the authors are estimating total ocean carbon uptake (i.e. air-sea carbon fluxes). They even compare their results with such estimates in the discussion. But this is not what the authors are calculating in this study. What is estimated here, is phytoplankton uptake of carbon, driven by the Fe supply from natural dust. I want to trust that this confusion is not a voluntary one by the authors. However, this must be corrected before the article can be published.
The use of the term ‘carbon uptake’ leads to some confusion. It is stated in the abstract that the authors refer to “phytoplankton carbon uptake”. But later in the text, it is termed “marine carbon uptake” (e.g. lines, 101, 103, 110, 132, 271). A good definition of the term ‘carbon uptake’ is central to the understanding of this manuscript. I recommend the authors clarify the term throughout the manuscript and refer to “phytoplankton carbon uptake”. Marine carbon uptake is very different from phytoplankton carbon uptake. In this study, the authors quantify phytoplankton carbon uptake, and not marine carbon uptake (which is mostly driven by physical factors).
Abstract:
The authors claim that their results show that iron dust deposition promotes “5.6 Pg C yr⁻¹ of carbon uptake by marine phytoplankton.” This value should be compared with the global uptake estimated without iron dust. Is this additional uptake significant?
Introduction:
Lines 113-122: I’m not certain that the paragraph on satellite observation is necessary here.
Methods:
2.1. Community Earth System Model
Some details are lacking. What is the time step of the model for emissions and depositions? What is the spatial resolution of the model? How many vertical levels are represented in the model?
Did you run simulations? Which forcings did you use? Which environmental conditions?
In Equation 1, the different factors should be properly defined: how do you define the tuning factor? What values does it take? Give the values and units of all variables.

Line 193: Replace “marine carbon uptake” by “phytoplankton carbon uptake”. This sentence should be moved to section 2.5.

Paragraph lines 198-203: What’s the time resolution of you simulations?

Line 239: “The dFe concentration data is a necessary factor for calculating the Fe: C ratio in phytoplankton cells”.

2.5 Calculation of Carbon Uptake
This section lacks details and precision, from which stem a lot of confusion. Dfe is concentration data taken from the GEOTRACES database (according to section 2.3), but on line 280, it is described as “dFe is the local concentration of soluble Fe”. Soluble and dissolved Fe are different things.
The definition of FeOpt should be detailed: is it the optimal Fe concentration in the water or in phytoplankton cells?
Finally, in order to avoid any confusion, the Fe:C ratio should be referred to Fe:C ratio in phytoplankton cells.
Line 275: “ambient soluble Fe” should be replaced by “dissolved Fe in seawater”.
Line 276: marine carbon uptake should be replaced by phytoplankton carbon uptake
The units of each term in Equation 4 should be described.

Results:
The results are presented with great details. However, most figures could be reworked to be simplified and easier to read.
The paragraph and associated figures on wet/dry deposition may be removed since you don’t discuss these results. Maybe they can remain in supplement, but I don’t find these results central to the study.
Figure 1: the names of the regions are difficult to read
Figure 2: The pie charts are almost impossible to see on the figure. The percentage already appears, so, maybe they can be removed.
Figures 3 and 7 could be grouped in 1 figure with 2 panels.
Figure 4: remove the pie charts. Describe the percentages either in the text or in the legend.
Figure 7 and 8 are very interesting, but I do not understand what the longitudinal columns with percentages represent. Maybe this could be simplified.
Figure 8 can go in supplement.
Figure 9: Remove the pie charts and change the legend to indicate that this is phytoplankton carbon uptake.
Figure 10 can go in supplement
Figure 11: change the legend to indicate that this is phytoplankton carbon uptake.
Figure 11 and 12 could be merged into 1 figure with 2 panels.
Figure 13: I do not understand the longitudinal columns. They can be removed to simplify the figure. Correct the legend to “phytoplankton carbon uptake”.

Lines 425-433: there is a lot of information that has already been described in the Methods. Some sentences can be removed (e.g. lines 431-433). Here specifically, the authors introduce a lot of confusion by writing “marine carbon uptake” instead of “phytoplankton carbon uptake”. Please change all occurrences to “phytoplankton carbon uptake”.

Lines 436-445: This seems to be discussion more than results.
Lines 441-445: “We estimated the global marine carbon uptake associated with new growth resulting from dust deposition, using the Fe:C ratio, since, regardless of whether in HNLC or LNLC regions, phytoplankton can respond to dust deposition. However, Fe is not the sole primary limiting nutrient in LNLC regions; therefore, we also quantified the marine carbon uptake resulting from new growth driven by dust deposition exclusively in HNLC regions.”. I don’t understand these statements.
Later (lines 499-501) it is stated: “Since Fe is the most primary limiting factor in HNLC regions, we estimated the result of marine carbon uptake for new growth induced by dust deposition only over HNLC regions.” Did you or did you not look at LNLC regions and why?

Discussion:
The discussion lacks some quantitative comparison of the author’s results with previous works.
For instance, the authors found that the Equatorial Indian and Atlantic oceans receive most of the global dust, and this dust is coming from the main emission sources. How did the author’s work bring novelty to these observations?
As currently written, the discussion repeats the results instead of putting the study results into perspective.
Lines 613-620: The comparison of the results with Mahowald’s results is very confusing and I think, false. This study quantifies carbon uptake by phytoplankton, it is in no way a translation of total carbon uptake by the ocean. The difference between this study and Mahowald’s results does not just stem from different methods, but on different objectives. This entire paragraph of discussion should be removed as these are not comparable results.

Lines 643-646: “Moreover, ecological models, such as the BEC model, incorporate various potentially growth-limiting nutrients and have ability to simulate different phytoplankton functional groups, which could be compared to our evaluation.” In this study, only Fe is considered a limiting nutrient for phytoplankton. You could discuss the implications of this assumption since, as stated here, other nutrients may limit or co-limit phytoplankton growth and carbon uptake.
Lines 646-648: The comparison with Westberry is also complicated here, primary production and phytoplankton carbon uptake are not strictly similar processes and may not be directly comparable. The following discussion on satellite data seems unecessary to the article.
The comparison with CMIP6 data should be more clearly explicited. Which models did you use? What variables did you compare your results to? Do all CMIP models use a variable Fe:C ratio for phytoplankton? How does that affect your comparison? Which years of CMIP simulations did you use? Which scenario?

-----------------------------------------------------------

Minor comments:
Abstract line 30: “Dust provides iron, which is an essential for marine phytoplankton growth,”
Line 36: “...based on a series of simulations…”
Line 47: replace “carrying’ by “carries” and add “be” before “deposited”.
Line 101: Rephrase to avoid the repetition of “carbon uptake” and clarify that you are talking about phytoplankton carbon uptake.
Line 136-137: “Fe:C ratios in phytoplankton cells […] to estimate the global carbon uptake by phytoplankton”
Line 140: replace “marine carbon uptake” by “phytoplankton carbon uptake”.
Line 211: “Fe solubility is also a key factor to estimate the carbon uptake of ocean to dust deposition” replace carbon uptake of ocean, by “carbon uptake of phytoplankton”.
Line 239: “The dFe concentration data is a necessary factor for calculating the Fe: C ratio.” Do you mean the Fe:C ratio of phytoplankton?

Citation: https://doi.org/10.5194/egusphere-2025-763-RC1
- AC1: 'Reply on comments from two reviewers', Jialei Zhu, 24 Jun 2025
  
  Please see our response in the supplement.
  
  Citation: https://doi.org/10.5194/egusphere-2025-763-AC1
RC2:
'Comment on egusphere-2025-763', Joan Llort, 06 Jun 2025

The manuscript provides interesting and relevant new insights into the regional and seasonal distribution of dust emissions and deposition. However, the results on phytoplankton carbon uptake linked to dust are less convincing and require additional work to be accepted for publication. See the attached file for details.

Citation: https://doi.org/10.5194/egusphere-2025-763-RC2
- AC1: 'Reply on comments from two reviewers', Jialei Zhu, 24 Jun 2025
  
  Please see our response in the supplement.
  
  Citation: https://doi.org/10.5194/egusphere-2025-763-AC1

Peer review completion

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

ED: Reconsider after major revisions (04 Jul 2025) by Frédéric Gazeau

ED: Reconsider after major revisions (04 Jul 2025) by Hermann Bange (Co-editor-in-chief)

AR by Jialei Zhu on behalf of the Authors (05 Jul 2025) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (07 Jul 2025) by Frédéric Gazeau

RR by Joan Llort (19 Jul 2025)

RR by Anonymous Referee #1 (11 Aug 2025)

Suggestions for revision or reasons for rejection

I want to thank the authors for taking the time to revise their manuscript and answer my questions. I think the manuscript has generally improved and I think it is almost ready for publication. I particularly thank the authors for their efforts on improving the clarity of the Figures. I have a few minor comments and one more general comment on the scope of the article.

Overall, I think the authors responded to most of my questions and comments and the manuscript is now clearer. However, I still believe that the most important and interesting contribution of this article is the dust source apportionment and quantification of each source region’s contribution to the global Fe ocean supply. The additional calculations regarding C uptake are highly uncertain and rely on hypotheses that I find too strong to be convincing. If not removed, at least the results regarding other regions than the HNLC regions should be properly discussed (i.e. how does the consideration of a linear relationship between [dFe] and Qfe influence the results? What about luxury uptake of Fe? How to decipher the effects of Fe with those from other limiting nutrients?…).

Minor comments:
Abstract line 30, remove “which is an”
Line 33 remove “phytoplankton”
Line 39 please add “11.1 Tg yr-1 of total iron …” to clarify.
Lines 39-40: remove “promoting 5.6 Pg C yr⁻¹ of carbon uptake by marine phytoplankton.”

Methods:
Sentence lines 226 and 238 are the same, remove one.
Line 286: I cannot find the Sunda (1995) reference in the reference list. Is the linear relationship between Qfe and [Dfe] valid everywhere and for all phytoplankton groups? I think this assumption needs to be justified.

Results:
Lines 442-443: “A small Fe: C ratio in phytoplankton cells indicates large marine phytoplankton carbon uptake driven by the same amount of Fe supply.” Replace ‘small Fe:C ratio’ by ‘something like ‘An Fe:C ratio lower than the optimal value’. It’s not the absolute value that counts but the distance to optimal Fe:C ratio.
In the next sentence: “Increased Fe supply usually can enhance carbon uptake by phytoplankton, but only soluble Fe is bioavailable,” Add “and Fe:C is lower the optimal value”.

Lines 450-454: The 2 sentences seem a bit contradictory. I think you can remove the 1st one.
Line 456: add “in HNLC regions at the end of the sentence”.

In methods, you say that the 3 HNLC regions are SO, EP and NP. And then you say that you only calculate the C uptake by phytoplankton driven by dust Fe in HNLC regions (because in other regions, the linear relation between Qfe and [dFe] doesn’t hold.
But lines 458-459, you mention Fe:C ratio in phytoplankton cells in the EA region. According to the methods, the calculation of the ratio shouldn’t hold for this region (which receives very large dust fluxes and is not Fe-limited). I think the interpretation of results for regions other than the HNLC region is not justified and should be removed (lines 455-485). Maybe this can be discussed in the paper. Same for the presentation of results on the seasonal uptake (lines 486-512).

Lines 513-517 are exactly the same as lines 450-454.
Again, phytoplankton may respond to dust addition in LNLC regions, but such areas are not Fe-limited and the linear relationship assumed between Qfe and [dFe] may not be verified in such regions. I cannot find the Sunda, 1995 referenced in the methods to justify this link in the reference list.

Discussion:
The hypotheses on around Equation X to calculate phytoplankton C uptake should be discussed. Is the relationship between Qfe and [Dfe] always linear? How does Fe phytoplankton uptake change with luxury uptake? Are there other hypotheses and works than the rather old Sunda 1995 paper on Qfe?
Fig4. If possible, please put boxes around each ocean region for clarity

Referee Report: PDF

Hide

ED: Reconsider after major revisions (28 Aug 2025) by Frédéric Gazeau

ED: Reconsider after major revisions (28 Aug 2025) by Hermann Bange (Co-editor-in-chief)

AR by Jialei Zhu on behalf of the Authors (04 Sep 2025) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (20 Sep 2025) by Frédéric Gazeau

ED: Publish subject to minor revisions (review by editor) (22 Sep 2025) by Hermann Bange (Co-editor-in-chief)

AR by Jialei Zhu on behalf of the Authors (23 Sep 2025) Author's response Author's tracked changes Manuscript

ED: Publish as is (02 Oct 2025) by Frédéric Gazeau

ED: Publish as is (05 Oct 2025) by Hermann Bange (Co-editor-in-chief)

AR by Jialei Zhu on behalf of the Authors (06 Oct 2025) Manuscript

Journal article(s) based on this preprint

06 Nov 2025

Tracing the contribution of dust origins on deposition and phytoplankton carbon uptake in global oceans

Yaxin Liu, Yunting Xiao, Lehui Cui, Qinghao Guo, Yiyang Sun, Pingqing Fu, Cong-Qiang Liu, and Jialei Zhu

Biogeosciences, 22, 6445–6464, https://doi.org/10.5194/bg-22-6445-2025,https://doi.org/10.5194/bg-22-6445-2025, 2025

Short summary

Yaxin Liu, Yunting Xiao, Lehui Cui, Qinghao Guo, Yiyang Sun, Pingqing Fu, Cong-Qiang Liu, and Jialei Zhu

Supplement

https://doi.org/10.5194/egusphere-2025-763-supplement

Yaxin Liu, Yunting Xiao, Lehui Cui, Qinghao Guo, Yiyang Sun, Pingqing Fu, Cong-Qiang Liu, and Jialei Zhu

Viewed

Total article views: 881 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	Supplement	BibTeX	EndNote
791	61	29	881	44	25	39

HTML: 791
PDF: 61
XML: 29
Total: 881
Supplement: 44
BibTeX: 25
EndNote: 39

Views and downloads (calculated since 06 Mar 2025)

Month	HTML	PDF	XML	Total
Mar 2025	101	15	6	122
Apr 2025	40	3	2	45
May 2025	14	6	4	24
Jun 2025	44	10	7	61
Jul 2025	31	5	1	37
Aug 2025	125	4	0	129
Sep 2025	392	6	5	403
Oct 2025	35	12	4	51
Nov 2025	9	0	9

Cumulative views and downloads (calculated since 06 Mar 2025)

Month	HTML	PDF	XML	Total
Mar 2025	101	15	6	122
Apr 2025	40	3	2	45
May 2025	14	6	4	24
Jun 2025	44	10	7	61
Jul 2025	31	5	1	37
Aug 2025	125	4	0	129
Sep 2025	392	6	5	403
Oct 2025	35	12	4	51
Nov 2025	9	0	9

Viewed (geographical distribution)

Total article views: 869 (including HTML, PDF, and XML) Thereof 869 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 06 Nov 2025

Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Preprint (2425 KB)
Metadata XML

Short summary

Dust carries iron deposits into the ocean, providing essential nutrients for the growth of marine phytoplankton, influencing their carbon uptake capacity. A model constrained by global datasets on dust iron content, ocean iron solubility, and dissolved iron concentrations was used to assess the contributions of 11 major dust sources to carbon uptake in 8 marine areas, enhancing understanding of the impact of global dust emissions on marine deposition and carbon cycle with decreased uncertainty.


Total:	0
HTML:	0
PDF:	0
XML:	0