Oolitic Limestone Induced by Photosynthetic Biofilms in the Xuzhuang Formation of Nangao Section, North China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This interesting and worth publishing manuscript could have been created thanks to the discovery of microbial remains very well preserved in the fossil record. For this reason, I suggest supplementing the manuscript with a short section explaining the mechanism of taphonomic processes allowing a good preservation of microbial structures.

The term Girvanella has a broad meaning and does not generally refer to one taxonomic genus. Therefore, I suggest that the name "Girvanella-like" should be used in relation to the structures studied by the authors. especially since determining the species of bacteria is not enough only to determine the shape and form. I also propose that the introduction include a short explanation about Girvanella and the occurrence of this form in the fossil record. e.g. publications may be helpful in this regard (by Jean-Paul Saint Martin, The Girvanella-like remains from Messinian marine deposits (Sardinia, Italy): Lagerstätten paradigm for microbial biota?, Annales de Paléontologie, 2010, Volume 96, Issue 2), and other like that.

 

Comments on the Quality of English Language

I recommend proofreading the text by an English native speaker

Author Response

Dear Reviewer,

I hope this message finds you well.

I am writing to express my sincere gratitude for the insightful comments and suggestions you have provided on my manuscript, titled Cerebroid Ooids Triggered by Photosynthetic Biofilms in the Xuzhuang Formation of Nangao Section, Jinan. Your expertise and foresight have been invaluable in enhancing the quality of my work. Regarding the specific comments you have raised:

1. **Taphonomic Processes**: As you suggested, I have supplemented the manuscript with a short section explaining the mechanism of taphonomic processes that allow for the good preservation of microbial structures. This addition has been made in the Materials and Methods section, which I believe will provide a clearer understanding of the processes involved.
2. **Terminology of "Girvanella-like"**: I appreciate your recommendation to use the term "Girvanella-like" in relation to the studied structures. However, considering that the term "Girvanella-like" is not widely used in the literature, I have modified some instances of "Girvanella" to "Girvanella Filaments" to maintain consistency with broader scientific usage. I apologize for any inconvenience this may cause and would like to offer a reference that also uses "Filaments" to denote Girvanella: Abdelfattah Azizi et al. (2023). Early biomineralization and exceptional preservation of the first thrombolite reefs with archaeocyaths in the lower Cambrian of the western Anti-Atlas, Morocco. Geological Magazine, 160(3), 428-443. 
3. **Species Determination and Introduction of Girvanella**: In response to your comment on the necessity of a comprehensive approach in determining bacterial species, I have added the requested content in the introduction. This includes a short explanation about Girvanella and its occurrence in the fossil record, which I hope will provide a more rounded context for the study.

Additionally, the manuscript has been polished further, and other revisions have been made, which will be reflected in the updated document I will upload. Once again, thank you for your constructive feedback. It has been an essential part of the revision process, and I am confident that these changes have significantly improved the manuscript. I am looking forward to the possibility of my work contributing to the scientific community thanks to your valuable input.

Best regards,

RX， Li

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Journal Editor,

Ruo-Xiang Li present a new interpretation of the role of biofilms on the formation of ooids. The author focused his research on the study of seven macroscopic and microscopic observations to analyze the depositional environment and genesis of oolitic limestone within the Xuzhuang Formation, Nangao section, China. Cerebroid ooids were observed with a high-density preservation of Girvanella in the nucleus. Clotted micrite structures were also observed. The author interprets the role of these biofilms as facilitating the formation of ooids between the festooned cortical morphologies and biofilms. Clotted micrite structures are interpreted as sponge remains.

The observation and interpretation of Ruo-Xiang Li are well detailed, well interpreted and justify for a publication in Minerals. The paper’s organization is good and well structured. The narrative and English are very impressive. The Introduction is well written, and complete. Other sections are relevant to understand the aim of the paper. The description of macro- and microscopic observations is very impressive, and in addition of the microphotography, the paper is enhanced by a good quality of analysis and interpretation. Discussion is well interpreted. The Conclusion is well written. Figures and photographs are informative in addition of the text that allows a good understanding of the aim of the paper. The references are complete.

I have no comments because the paper is very impressive and well done. These new observations are an important finding worthy of publication and one, which should be more widely known and appreciated by other workers. I recommend “acceptable for publication”.

 

Author Response

Dear Reviewer，

I hope this letter finds you in good health and high spirits. I am writing to convey my heartfelt appreciation for your recognition and support of my manuscript entitled "Cerebroid Ooids Triggered by Photosynthetic Biofilms in the Xuzhuang Formation of Nangao Section, Jinan" which I recently submitted for your review. I am particularly grateful for the positive feedback you provided, which has been a source of encouragement. Nonetheless, in the spirit of academic rigor and excellence, I have taken into account the constructive comments provided by the other reviewers. Inspired by their insights, I have made several substantive changes to the manuscript to refine the arguments, enhance the clarity, and strengthen the overall contribution of the work.

Furthermore, I have invested additional effort to ensure the language and presentation of the manuscript are of the highest standard. To this end, I have engaged in a thorough language polishing process to improve readability and ensure that the academic content is clearly communicated. These revisions and enhancements will be evident in the updated document that I will upload shortly. I am confident that these changes have not only addressed the reviewers' concerns but have also elevated the quality of the manuscript, making it a more fitting contribution to the scholarly discourse. I am eager to see the final version of the manuscript advance through the publication process and I am hopeful that it will make a valuable addition to the field.

Thank you once again for your support and for the role you have played in refining this piece of research.

Warm regards,

RX， Li

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Ruo-Xiang Li considers the genesis of cerebroid ooids in the Cambrian Xuzhuang Formation. The author infers a biofilm influence on the cerebroid coating, providing plausible arguments as to why this might be the case. Ruo-Xiang Li also considers the nature of sparry microtubules in the clotted micrite that occurs between the ooids. The author’s comments about biofilms and cerebroid ooids are plausible, as I mentioned above. However, the most important part of the paper is where the author considers the sparry microtubules in the clotted micrite. This is thus an important paper. However, the manuscript must undergo major revision as described below before publication.

 

The author states (lines 362-363) that ‘the cloted micrite structure has difficulties in genetic interpretation.' That is correct. Please refer to the following article for a detailed analysis of the problem:

 

Neuweiler, F., Kershaw, S., Boulvain, F., Matysik, M., Sendino, C., McMenamin, M., Munnecke, A. 2022. Keratose sponges in ancient carbonates—a problem of interpretation. Sedimentology, doi: 10.1111/sed.13059.

 

Ruo-Xiang Li correctly notes that the clotted micrite with sparry tubules may represent (line 382) a ‘possible small cave’ (= cryptic cavity). I agree with this statement.

This does indeed represent a cryptic cavity. The author also notes (line 393) that the ‘unevenness of the thickness of the sparry microtubules’ argues against a sponge spicule interpretation of the structures. I agree, in fact these structures are the microburrows of microburrow cavity nests described in 2016. See Chapter 12 in:

 

McMenamin, M. A. S. 2016. Dynamic Paleontology: Using Quantification and Other Tools to Decipher the History of Life. Springer International Publishing, Cham, Switzerland. 251 p. Hardcover ISBN 978-3-319-22776-4; eBook ISBN 978-3-319-22777-1.

 

In this same book, note the ethmophylloid archaeocyath with cerebroid coating illustrated in Fig. 6.6.

 

Sparry microtubules (microburrows) may very well represent the oldest evidence for metazoans. The 890 Ma age reported in Reference 41 is not too old for this; these trace fossils represent the most ancient discovery of metazoan trace fossils. See:

 

Kris, A., McMenamin, M. 2021. Putative sponge spicules reinterpreted as microburrows. Academia Letters, Article AL3800, https://doi.org/10.20935/AL3800

 

Ruo-Xiang Li’s speculation (line 424) that the 'sparry microtubules are gas bubbles’ is very unlikely. Gas bubble tracks would not resemble these structures. The structures are much more likely to be microburrows.

 

Comments on the manuscript:

 

44-45   Tucker & Wright quote, is this the correct quote? It does not seem correct.

 

145       replace Frequently with Frequent

 

190       Fig. 5c shows a microburrow right under the scale bar

 

192        remove ';' after nucleus

 

230ff    Fig. 6c seems to be missing

 

230       Fig. 7.a should be Fig. 7a

 

230ff.   Why do you use the term radiolarite? I see no evidence of radiolarians.

 

275-277  Fig. 9 caption: I can find neither 5g nor 6a

 

292, 346  Put Girvanella in italics

 

297          define CCM (carbon concentrating mechanisms) the first time you use it in                    the text

Comments on the Quality of English Language

n/a

Author Response

Dear Reviewer,

I would like to extend my sincere thanks for your attention to my manuscript titled "Cerebroid Ooids Triggered by Photosynthetic Biofilms in the Xuzhuang Formation of Nangao Section, Jinan" and for the constructive comments that have significantly contributed to its improvement. I have carefully considered each of your suggestions and have made the following revisions accordingly:

1. The reference you requested on lines 362-363 has now been duly cited in the manuscript.
2. In regards to the concept of "microtubules," I have reviewed the literature you provided, including "Dynamic Paleontology: Using Quantification and Other Tools to Decipher the History of Life." Based on my understanding, this reference interprets "microtubules" as a potential trace fossil and presents intriguing observations. However, it appears that there is no consensus in the academic community on this interpretation. The following references offer alternative explanations for similar phenomena:
   1.  Lee, J.H., Riding, R. The 'classic stromatolite' Cryptozoon is a keratose sponge-microbial consortium. Geobiology, 2021, 19(2), 189-98. 
   2.  Luo, C.; Pei, Y.; Richoz, S., et al. Identification and Current Palaeobiological Understanding of "Keratosa"-Type Nonspicular Demosponge Fossils in Carbonates: With a New Example from the Lowermost Triassic, Armenia. Life-Basel, 2022, 12(9). 
   3.  Brayard, A.; Vennin, E.; Olivier, N., et al. Transient metazoan reefs in the aftermath of the end-Permian mass extinction. Nature Geoscience, 2011, 4(10), 693-7.

Consequently, I have included the interpretation mentioned in your reference as one of the possible explanations in the discussion section, rather than the sole explanation. This is not to suggest that there is an issue with the interpretation in your reference, which I find insightful. Additionally, the interpretation of trace fossils, based on the evidence provided in this paper, has some uncertainties. Firstly, the structures in this paper do not exhibit the typical distinct continuous boundaries as described in the references. Secondly, the preservation mechanism for such microscopic traces in the oolitic limestone depositional environment is difficult to explain, which is why it is not presented as a conclusion.

3. The incorrect Tucker & Wright quote has been corrected.

4. The abbreviation CCM has been defined at its first occurrence in the text.

5. The misuse of the term "radiolarite" has been corrected. Indeed, I intended to refer to "radial ooids."

6. Issues related to grammar, punctuation, and incorrect figure references have been addressed.

All other changes have been annotated in the revised document that has been uploaded. The manuscript has also undergone language polishing to ensure clarity and coherence.

I trust that these revisions will meet with your approval, and I am open to any further suggestions you may have. Thank you once again for your invaluable feedback and assistance in enhancing the quality of my work.

Warm regards,

RX， Li

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

See attached file, please!

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

I hope this message finds you well. I am writing to express my gratitude for the detailed review and valuable suggestions you have provided for my manuscript, titled “Cerebroid Ooids Triggered by Photosynthetic Biofilms in the Xuzhuang Formation of Nangao Section, Jinan”. Your insights have played a significant role in the improvement of my paper, and I have made several revisions based on your recommendations, which will be reflected in the revised document that I am preparing to upload.

I would like to address a few points where my revisions diverge from your suggestions, and I hope to discuss these with you to reach a mutual understanding:

 

Regarding Comment 2: In line with the template provided by the Minerals journal and the format observed in previously published articles, I have maintained the Geological Setting as Chapter 2, following it with the Materials and Methods section. This organization is consistent with the structure commonly adopted in geological publications.

Pertaining to Comment 20: I have verified the Formation names following your comments and cross-referenced them with the literature:

[1] Mei, M.X.; Riaz, M.; Zhang, Z.W., et al. Diversified calcimicrobes in dendrolites of the Zhangxia Formation, Miaolingian Series (Middle Cambrian) of the North China craton. Journal of Palaeogeography-English, 2021, 10.

[2] Peng, S. (2012). The Geologic Time Scale || The Cambrian Period. , (), 437–488. doi:10.1016/b978-0-444-59425-9.00019-6

The names, as used in my manuscript, are indeed correct. To clarify this, I have added an explanation to Figure 2a. Nonetheless, I am grateful for your attention to detail and the opportunity to ensure the accuracy of the geological terminology used.

 

In relation to Comment 46: I have thoroughly reviewed the introduction of my paper, and I am confident that the content is well-supported by conclusions drawn from published journals, without the inclusion of any unsubstantiated personal conclusions. While I deeply value your feedback, I have decided against adding any new conclusions at this stage. I kindly ask for your understanding on this matter.

I hope that my responses to the above points meet with your approval. All other revisions have been annotated in the uploaded document, and the article has been subjected to language polishing to enhance its clarity and readability.

I am looking forward to your acknowledgement of these revisions and to any further guidance you may provide. Thank you once again for your significant contribution to the refinement of my manuscript.

Warm regards,

RX，Li

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

You have successfully responded to my comments on the earlier version of this manuscript. 

Comments on the Quality of English Language

Reference 43 should be corrected to read: "Paleontology: Using"