Estimation of Mariculture Carbon Sinks in China and Its Influencing Factors

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Jmse 2024

Mariculture carbon sinks in China: assessment and its influencing factors

First-round review

Comments and suggestions

The Chinese references, very numerous (28/37), are clearly relevant. International literature would benefit from knowing them better and quoting them. However, in many cases the manuscript should cite additional references. See example hereafter.

Lines 45-46. ‘Carbon sequestration through marine ecosystems has also become a popular field of carbon sink research in recent years[4]’. The authors cite only one reference, and it concerns mariculture. Many references relate to natural ecosystems, such as mangroves and seagrass meadows, and should be cited. See e.g.:

Cuellar-Martinez T., Ruiz-Fernández A.C., Sanchez-Cabeza J.A., Pérez-Bernal L., López-Mendoza P.G., Carnero-Bravo V., Agraz-Hernández C.M., Van Tussenbroek B.I., Sandoval-Gil J., Cardoso-Mohedano J.G., Vásquez-Molina Y., Aldana-Gutiérrez G., 2020.  Temporal records of organic carbon stocks and burial rates in Mexican blue carbon coastal ecosystems through the Anthropocene. Global and Planetary Change, 192 (103215): 1-15.

Monnier B., Pergent G., Mateo M.Á., Clabaut P., Pergent-Martini C., 2022. Quantification of blue carbon stocks associated with Posidonia oceanica seagrass meadows in Corsica (NW Mediterranean). Science of the Total Environment, 838 (155864): 1-14.

The authors should indicate the species names of oysters, mussels, scallop, clams, blood clam, razor clam, kelp (a customary term which includes many brown seaweed genera, including wakame), wakame, nori and Gracilaria. Why does the order in which these taxa are listed change from one table or figure to another? E.g. kelp-wakame-Gracilaria-nori (table 1) and kelp-wakame-nori-Gracilaria (Table 4). E.g. oyster-mussel-scallop-clam (Fig. 9), clam-scallop-oyster-mussel-blood clam-razor clam (Table2), scallop-oyster-clam (Table 3) and oyster-blood clam-mussel-scallop-clam-razor clam (Table 4).

The authors seem to use ‘seaweeds’, ‘macroalgae’ and even ‘algae’ (e.g. Fig. 1) as synonyms. It would be good to specify in the introduction that macroalgae and seaweeds, used as synonyms, correspond to multicellular photosynthetic organisms, a polyphyletic group without taxonomic value. Please choose a term (e.g. seaweeds); avoid the term ‘algae’ (Fig. 1).

In chapter 1 (introduction), the notion of removable carbon sink (or fishery carbon sink) and the dilemma of shellfish carbon fixation via calcification (source or sink?) are well described. However, the distinction between short-term sequestration (a few months or years) in short-lived organisms (e.g. macroalgae and molluscans), and long-term sequestration (centuries to millennia) in sediment should be addressed. This is the case for mangroves, certain seagrasses (Posidonia and Thalassia) and coastal lagoons. Long-term sequestration is only mentioned through the recalcitrant dissolved organic carbon (RDOC). It also appears in the results section (e.g. line 348). Short-term vs. long-term sequestration should also be addressed in the abstract.

A reflection on the concept of a removable carbon sink would be interesting: once consumed by humans (shellfish, wakame, nori), or industrially processed (kelp, Gracilaria), the carbon returns to the atmosphere. Isn't the sink very short-termed?

The number of figures is very high. I'm not sure they are all useful. it would be better to choose those that best support the conclusions.

Line 130. Chinese Ministry.

Line 140. ‘The main species of mariculture seaweeds include kelp, wakame, nori, and gracilaria’. Please specify Latin names (e.g. Undaria pinnatifida for wakame).

Line 141. ‘four species’: wakame (Undaria pinnatifida) and kelp (Saccharina japonica?) correspond to species, but what about nori and gracilaria? Please do not use the term of kelp: kelp is a very general customary term for many large brown seaweeds; wakame belongs to kelp!

Line 143 (and the whole manuscript). ‘weight’? No: mass. The SI unit for weight is the newton (N), while the SI unit for mass is the kilogram (kg). Obviously, you mean mass!

Line 153. Fishery Statistical Yearbook: reference, please.

Table 2. ‘varieties’ à ‘taxa’. Please capitalize the first letter of ‘blood clam’ and ‘razor clam’.

Line 178. a and b.

Table 3. Please give the same number of decimals in a given column. 1.79 does not means 1.790 but ‘between 1.785 and 1.794.

Line 223. ‘structure factor (SSF), efficiency factor (SEF), and scale factor (SMF)’: why structure factor ‘acronym is SSF? Efficiency factor SEF? Scale factor, SMF?

Line 234. Variety? Rather ‘taxon’.

Figure 2. algae à seaweeds (or macroalgae: thank you for choosing).

Figure 2. The authors should indicate that the scale (left side) concerns either shellfish OR seaweeds, while the right side’ scale applies to shellfish AND seaweeds.

Line 307. 1000 à 1,000.

Line 325. species à taxa.

Figure 4b. Algae à seaweeds (or macroalgae: thanks for choosing).

Line 327. Species à taxa.

Figure 11. Algae à seaweeds (or macroalgae: thanks for choosing).

Line 476. 3060t à 3,060 t

Line 546. ‘many countries’: which ones?

Conclusions

The submitted article is interesting. It concerns a vast geographical area, and several taxa, so that its scope is not just anecdotal and local, but general. It therefore deserves to be published.

However, it contains too many errors in form. In addition, reflection on carbon sinks should be more critical, in particular with the distinction between very short-term (can we really speak of carbon sinks?) and long-term (real carbon sinks?).

For these reasons, I suggest accepting this article with major revision.

Second-round review

The revised version of the manuscript well responds my first-round suggestions. In addition, please consider the following suggestions.

Lines 12-13. Unclear. ‘The highlight is that the distinction between removable short-term carbon sequestration in seaweed and shellfish and deposited long-term carbon sequestration in this paper’ à ‘The paper highlights the distinction between removable short-term carbon sequestration in seaweed and shellfish and deposited long-term carbon sequestration’

Line 49, references [5] and [6]: The first and last name of the authors have been swapped!

Tomasa C ,Carolina A R ,Joan-Albert S , et al. Temporal records of organic carbon stocks and burial rates in Mexican blue carbon coastal ecosystems throughout the Anthropocene[J].Global and Planetary Change,2020,192(103215):1-15 à Cuellar-Martinez T, Ruiz-Fernandez AC, Sanchez-Cabeza JA

Briac M ,Gérard P ,Ángel M M , et al. Quantification of blue carbon stocks associated with Posidonia oceanica seagrass meadows in Corsica (NW Mediterranean).[J].The Science of the total environment,2022,838(P1):155864-155864. à Monnier B, Pergent G, Mateo AM

Lines 58-61. Seaweeds and macroalgae are just synonyms. ‘Seaweeds and macroalgae are types of algae. They are corresponding to multicellular photosynthetic organisms, a polyphyletic group without taxonomic value. But algae are unicellular or multicellular marine organisms. The taxa studied so far fall under the category of seaweeds’ à ‘Seaweeds (= macroalgae) correspond to a polyphyletic group of multicellular photosynthetic organisms without taxonomic value. The taxa studied so far fall under the category of seaweeds.’ Cite e.g. Boudouresque et al. (2015):

Boudouresque C.F., Caumette P., Bertrand J.C., Normand P., Sime-Ngando T., 2015. Systematic and evolution of microorganisms: general concepts. In: Environmental microbiology: Fundamentals and applications. Microbial ecology. Bertrand J.C., Caumette P., Lebaron P., Matheron R., Normand P., Sime-Ngando T. (eds.), Springer publ.: 107-144.

Line 188. Laminaria japonica: the correct name is Saccharina japonica. Please use italics for species and genus names!

Line 189. Porphyra à Porphyra-like species (the ancient genus Porphyra has been split into several genera). Or à Porphyra sensu lato.

Line 197. Laminaria japonica à Saccharina japonica. Undaria pinnatifida and Gracilaria ferox : italics! Porphyra à Porphyra sensu lato.

Line 217 (table 2). Please give the Latin names of oyster (Magallana gigas), blood clam, mussel, scallop and razor clam.

Line 251 (table 3). Please give Latin names. Especially when dealing with clams, since several species are listed in table 2 (blood clam and razor clam)

Lines 337-338. Laminaria japonica à Saccharina japonica.

Line 339. Undaria pinnatifida à Undaria pinnatifida (italics!)

Line 350. to remove carbon sinks à to fix carbon

Line 354. Carbon sinks in seagrass beds, mangroves and coastal lagoons are long-term sinks. See e.g.:

Barbier E.B., Hacker S.D., Kennedy C.J., Koch E.W., Stier A.C., Silliman B.R., 2011. The value of estuarine and coastal ecosystem services. Ecological Monographs, 81 (2): 169-193.

Cuellar-Martinez T., Ruiz-Fernández A.C., Sanchez-Cabeza J.A., Pérez-Bernal L., López-Mendoza P.G., Carnero-Bravo V., Agraz-Hernández C.M., Van Tussenbroek B.I., Sandoval-Gil J., Cardoso-Mohedano J.G., Vásquez-Molina Y., Aldana-Gutiérrez G., 2020. Temporal records of organic carbon stocks and burial rates in Mexican blue carbon coastal ecosystems through the Anthropocene. Global and Planetary Change, 192 (103215): 1-15.

Duke N.C., Meynecke J.O., Dittmann S., Ellison A.M., Anger K., Cannicci S., Diele K., Ewel K.C., Field C.D., Koedam N., Lee S.Y., Marchand C., Nordhaus I., Dahdouh-Guebas F., 2007. A world without mangroves? Science, 317: 41-42.

Pergent P., Bazairi H., Bianchi C.N., Boudouresque C.F., Buia M.C., Calvo S., Clabaut P., Harmelin-Vivien M., Mateo M.A., Montefalcone M., Morri C., Orfanidis S., Pergent-Martini C., Semroud R., Serrano O., Thibaut T., Tomasello A., Verlaque M., 2014. Climate change and Mediterranean seagrass meadows: a synopsis for environmental managers. Mediterranean Marine Science, 15 (2): 462-473.

Line 364. Biomass mass à biomass.

Line 512. Caption to Fig. 11. A figure should be understandable without reading the text of the article. Please define STF, EFF and SGF.

Line 545 (Table 4). Laminaria japonica à Saccharina japonica. Undaria pinnatifida : italics ! Pophyra à Porphyra sensu lato. Gracilaria ferox : italics !

Line 583. Laminaria japonica à Saccharina japonica.

Please, carefully check the English language with a native English speaker.

Conclusion

The ms can now be accepted with minor revision

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

This article has been improved since the first submission. Here, an important contribution for the climate change mitigation related to the management of mariculture carbon sinks is reported. I suggest to accept the manuscript for the publication.

Kind regards

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

Breve resumen 

Estimados autores:

Siguiendo las pautas éticas de COPE para revisores pares, me complace presentar el informe de revisión del artículo:

Sumideros de carbono en la maricultura en China: evaluación y sus factores que influyen

Lo he leído atentamente en su totalidad, agradeciendo a los autores su esfuerzo y dedicación en su elaboración y considero a la Revista Marine Science and Engieneering para su revisión y posible publicación.

El objetivo del Manuscrito era:

"Este artículo mejoró el modelo de estimación del sumidero de carbono de la maricultura al considerar la tasa de deposición de carbono orgánico y la tasa de entierro de diferentes variedades de mariscos en diversas áreas marinas, basándose en el mecanismo de secuestro de carbono y las vías sistemáticas de secuestro de carbono en mariscos y algas marinas ".

Es un interesante artículo de investigación que investiga una variable importante: el sumidero de carbono de la maricultura y sus factores que influyen.

“From 2010 to 2020, the carbon sequestration of offshore seaweeds aquaculture in China amounted to 7,959  Mt  C/a,  with  a  removable  carbon  sequestration  of  6.049  million  tons.  Additionally, shellfish aquaculture contributed the carbon sinks of 33.542 Mt C/a, among which the removable carbon from shellfish biomass and carbon sequestration of shellfish deposition are 12.386 and 21.167 million tons, respectively. Sedimentary carbon sequestration by shellfish accounted for 51% of the total carbon sequestration in mariculture involving shellfish and seaweeds, making it an indispensable and crucial component of mariculture carbon sequestration estimation. To different coastal provinces of  China,  the  removal  carbon  sink  capacity  of  shellfish  and  seaweeds mariculture in Shandong Province and Fujian Province were 5.428 million tons and 5.215 million tons, accounting for 29.4% and 28.3% of the total removable carbon sink of China’s mariculture respectively. Using the LMDI decomposition model, the factors that enhanced the carbon sink.

The authors conclude that:

The findings revealed that improvements in farming efficiency exerted the greatest influence on the mariculture carbon sink variations, while adjustments in farming structure had a relatively minor impact in the case of little change in aquaculture yield. Enhancing farming efficiency emerges as a practical approach to bolstering the carbon sink potential of marine aquaculture fisheries.

 Because of the format in which the manuscript was presented, I think that it has already been revised on some occasion, since the authors send comments in the revision panel.

I was not informed about this, so my comments to the manuscript will be considered as a first revision, but of course I will take into account what was added in a different color.

 SPECIFIC COMMENTS

NOTE 1. TITLE:

Mariculture carbon sinks in China: Assessment and its influencing factors

In my opinion, in the title it is clear what the authors intend to convey, but it does not contain some epistemological elements in scientific research in its structure and order.. 

The object of study: The variables: carbon sinks , influencing factors

The subject of study:  Mariculture in China   

The method: Assessment (not appropriate) Estimation is correct and in accordance with what is reported in the results section.

In my opinion, the title could be clearer for the readers due to what is reported in the results section the authors made estimates, therefore the word assessment is not appropriate, in the results section the subtypes are clearly specified:

3.1. Estimation of removable carbon sink of shellfish and seaweeds in China.

3.2. Estimation of photosynthetic carbon sequestration intensity of mariculture seaweed.

3.3. Estimation of carbon sequestration by shellfish deposition.

 Therefore, I propose the following titles for the consideration of the authors:

1.- Estimation of carbon sinks of Mariculture in China and the influencing factors

2.- Estimation of carbon sinks of Mariculture in China.

This second title does not include the influencing factors, because it is an effect variable, the central issue is the estimation and as a consequence, the factors are identified.

Clear and consistent.

In this way a title is supported:

I hope you take this as a constructive idea, the freedom of naming the work is only of the authors.

This title is in accordance with the general objective.

 NOTE 2. THE ABSTRACT:

Is the most read section of an article, so it is important that it is orderly, trying to separate the sections.

The introductory paragraph is appropriate;

” he scientific assessment of mariculture carbon sinks is crucial to recognize its potential as a significant component of marine blue carbon in global climate change mitigation

Add.

Therefore, the objective of the research was…………

Methodologically......................................

the results indicated......................

It is concluded ...........................................

The summary with the way it is structured can be improved, to motivate readers to read the article in extenso, I suggest that the conclusions are based on the objectives and considered the problem statement and research questions. Do not forget the originality of the work, because studies of carbon sinks of Mariculture are limited? what is the difference of this work?

I suggest highlighting it appropriately.

“An abstract providing key information about the main objective(s) or question(s) that the review addresses, methods, results, and implications of the findings should help readers decide whether to access the full report “ Beller, et al. 2013.

 I suggest you try to rewrite the abstract in the suggested order

 NOTE 3.-KEYWORDS:   Removable carbon sink; bio-deposited carbon sink; shellfish and seaweeds mariculture; mariculture carbon sink estimation model; LMDI decomposition

Keywords are important for the editorials for indexing purposes, a proposed idea is that the words included in the title are not repeated in the keywords, it would be interesting to place a keyword that is related to ODS addressed.  Eliminate mariculture carbon sink estimation model

Add:   Life below water

NOTE 4. INTRODUCCIÓN

All references are in the wrong format, they are not in superscript, please check the author's guide.

Example 1. North America to South America [1], [2], [3].

 Line 41. exacerbated the global greenhouse effect. Reference (Historical evidence  )

 Line 42. China pledges to strive for a CO₂ emissions peak in 2030 and strives to achieve carbon neutrality by 2060 in order to cope with the global climate change issue. Reference (Historical evidence  )

 Line 51 to 93.  The paragraph is too long, I suggest the authors use paragraphs of 150 to 170 words, to facilitate the reading of the manuscript.

 Line 74 “Several scholars have evaluated the carbon sink capacity of seaweeds by using the macroalgae carbon sink measurement method”.

Who?  Add references 

Line 59. “Seaweeds and macroalgae are types of algae. They are corresponding to multicellular photosynthetic organisms, a polyphyletic group without taxonomic value. But algae are unicellular or multicellular marine organisms. The taxa studied so far fall under the category of seaweeds”. References.     

This small paragraph has some dots, the idea to be transmitted is not understood, and there is a lack of references when using the word studied.

 Line 83. Under the condition of considering POC and DOC, the carbon sink of mariculture seawee

The first time acronyms are used, they should indicate their meaning.

Line 102. At present, the majority of scholars have come to recognize the calcification mechanism that the generation of every 1 mol of calcium carbonate will release 1 mol of CO2 into seawater, and the reaction formula is as follows: Ca2+−+2HCO3=CaCO3+CO2 ↑ +H2O.

It is a numerical data, add reference.

Line 107. However, 2 mol of bicarbonate can be absorbed from seawater during the calcification process

It is a numerical data, add reference.

Line 112. “On the other hand, shellfish have a very effective filter-feeding system combined with a high filtration rate, which can synthesize their material by ingesting and assimilating. It can promote the growth of soft tissue and fix carbon in seawater.”

Add reference.

Line 124. “In Sango Bay, the field measured data showed that the mussel bio-deposition carbon Weight sequestration was more than three times that of the removable carbon sequestration [26]. Using the carbon budget method to study the growth process of the long oyster in the Sango Bay region demonstrated the significance of biological deposition. An oyster used 15g C/a in the water during the cultivation period, of which 24% of the shell carbon sequestration and 2.9% of the carbon promoted the growth of soft tissue. And biological sediments fixed around 22.2% of the carbon [26].

This paragraph is from a reference [26]. should be written better.

 Line 131. In general, the carbon sink function of mariculture shellfish is highly effective and significantIt is critical to clarify the different storage time of carbon sinks. The storage cycle of carbon in mariculture are related to carbon processed way. During the growth, seaweeds and shellfish sequester biomass carbon is rapidly converted to carbon dioxide and released to the atmosphere after processed or consumed. Therefore, it is necessary to discuss the processing and consumption in the form of carbon footprints in next step.

 Line 139. The existing mariculture carbon sink” only contains the carbon biomass by harvesting shellfish and seaweed “removable organisms. The focus on the controversy is how long this removable carbon can be stored out of the atmosphere. Indeed, the different treatments or processing of the from the water, harvested have a major impact on the carbon storage time. If the shellfish and seaweeds are used for food, it would be reconverted into CO₂ and released back to the atmosphere, unable to form a long-term carbon sink. However, if it is used to produce biofuels, it can reduce to a certain extent the carbon emissions caused by burning fossil fuels, which can be considered another form of “emission reduction”. while with the growth of seaweeds and shellfish, they absorb CO₂ from the atmosphere and fix a large amount of organic carbon, such as dissolved organic carbon. The particulate organic carbon formed by biological pumps is ultimately deposited and buried on the seafloor or transported to the deep sea through direct subsidence [32]. Organic carbon in seawater depends on micro bio-pumps to form stable RDOC. The total carbon of RDOC is equivalent to the harvested carbon biomass [23]. It can be fixed for a long period and stored for tens of thousands of years [33,34,35].

These paragraphs should be better structured, the points are not adequately placed in the paragraphs, besides they are statements that should have an empirical basis, therefore, references should be added, the carbon cycle should be considered.

  Authors should start with the field of knowledge addressed, and structure the introduction appropriately.

In order to structure their research objective, it is important to emphasize the relevance of the papler and the need to find aspects that have not been studied in the evidence.

. I suggest the authors answer the following questions and analyse the introduction section:

1. Is it focused on the problem clearly from macro to micro?

2. Is it enjoyable and fruitful to read, does it condense the letters and is it prolific in ideas?

3. Does it clearly state the reasons for conducting the study?

4. Does it state the premises on which the study is based?

5. Does it clearly define the objectives of the study? 

6. Does it state the hypotheses that the study intends to demonstrate?

 NOTE 5. THE OBJECTIVE

Regarding the objective, there is no consistency between the objective stated in the abstract, nor in the title of the paper.

In the introduction:

Estimate the carbon sink capacity of mariculture shellfish and seaweeds in China’s coastal regions from 2010 to 2020.

 In Abstract:

“Estimation model of mariculture carbon sink by considering the organic carbon deposition rate and burial rate of different shellfish varieties in various sea areas, based on the carbon sequestration mechanism and systematic pathways of carbon sequestration in shellfish and seaweeds.”

 Title:

Mariculture carbon sinks in China: Assessment and its influencing factors

 The title does not correspond to the objectives, and suggestions for objectives:

a) The appropriate verb is Estimate for the variable 1. which is the central axis of the work (carbon sinks).

b) And for the factors you could use the verb    (identify the factors ......).

 NOTE 4. THE HYPOTHESIS

They do not present working hypotheses. Normally, after reading extensively about a topic, it is advisable to propose working hypotheses, which should be aligned with the evidence base.

 NOTE 5. METHODOLOGY

Recommendations:

1.- Did you provide all the necessary information about the variables studied and the products used (doses, origin, etc.)?

 2.-Did you include all the methods used in the study?

 3.-Did you describe them in detail?

4.-Did you correctly cite the methods?

5.-Are the statistical procedures rigorous?

6.-Is the use of data description and statistical treatment consistent?

7.-These are reflection questions that support your work.

I suggest organizing the methodology as follows:

2. Materials and methods

2.1. Study site

Recomiendo describir con datos geográficos, climáticos que ubique a los lectores donde se realizo el trabajo, puede utilizar solo texto, o imágenes satelitales.

2.2. Construction of carbon sink accounting system for mariculture shellfish and seaweeds

Line 175. Among them, the data of different species output and area were obtained from the China Fisheries Statistical Yearbook (2010-2020).

Add reference.

Line 176. The calculation method is based on the industry standard of the Marine Carbon Sink Accounting Method (HY/T 0349-2022) that approved by the Chinese Ministry of Natural Resources.

Add reference.

Line 178. the POC and DOC of mariculture seaweeds are calculated with the experience coefficient. The shellfish deposition carbon sequestration is considered from the perspective of organic carbon burial rate. The shellfish deposition carbon sequestration model was established by using the mariculture area and the organic carbon deposition rate.

Add references.

Line 184. Figure 1. Carbon sink accounting system of the mariculture shellfish and seaweeds in offshore China

Mejorar la calidad de la figura sobre todo en el tipo de leta, que sea uniforme y del mismo tamaño.

Flowcharts are a very appropriate tool to show the methodology followed in a work, it is a way where the authors make an effort to synthesize in a diagram what they did, however the decision symbol is confusing, try to follow the flowchart standard or change that symbol.

 It is confusing, try to follow the norm of flowcharts or change that symbol if it is not a decision.

The arrows indicate the flow from start to finish, check that the arrows follow an order, for example: from Seaweeds removable carbon sequestration to phosysinthetic sequestration.

2.3.  The measurement method of carbon sink of mariculture shellfish and seaweedsPrimary growth in aseptic condition

Line 188. The main species of mariculture seaweeds include Laminaria japonica, Undariapinnatifida, Porphyra, and Gracilaria ferox. The output of these four species accounts for kelp more than 95% of the total mariculture seaweeds output in the country. Add Reference and use cursivas para las especies de algas.

Line 193. Las ecuaciones deben ser numeradas.

Linea 198. The species of mariculture shellfish mainly include oysters, blood clams, mussels,scallops, clams, and razor clams, and the total output of six species account for more Wakame than 91% of the output of mariculture shellfish in China.

Add reference.

( # ) what does it mean in equations ?

Table 2. Mass proportion and carbon content of different taxa of shellfish software tissue and shell

References [7, 38,40] is for which species

Use scientific names

Line 232. the shellfish bio-deposition carbon sequestration is an important part of the carbon β sink in the shellfish mariculture. It can eventually be buried in the seabed for more than thousands of years and transported to the deep sea. From the perspective of organic carbon embedment of mariculture shellfish, the carbon sequestration amount of biological sediment is calculated as follows:

Add reference.

Bi = OVi × Si × T × Em  

Equation number and reference.

Table 3. Biological deposition rate, organic carbon content and organic carbon mineralization rate of different species and sizes shellfish in different sea areas.

References [42, 43,44,41] for which species and the others?

Use scientific names.

In all tables, please follow the instructions in the authors' guide.

2.4. Decomposition of influencing factors of mariculture carbon sink

2.5 Statistical analysis and software

  Example of software use: Statistica 10 software (StatSoft,Tulsa,OK).

NOTE 6. RESULTS  

Recommendation: 

Is the parallelism between the presentation of results in text and the presentation of data in tables and figures perfect?

 1.-Does the order of presentation of the different types of results follow a logical order?

2.-Have you highlighted the star results?

3.-Is it clear in all comparisons which values are compared and which test is used for comparison?

4.-Can you present the data in a more concise way?

The order of the results should be structured in the study variables according to the methodology.

Present your results in order. Ok

Fig..2 showed ( do not abbreviate the word).

Line 333 a 355

 Figure 3(a). Removable carbon sink of different taxa of shellfish in different provinces.

Figure 3(b). Removable carbon sink of different taxa of seaweeds in different provinces.

Figure 6. Sedimentary carbon sequestration of different species of shellfish in different provinces.

 They are very small, if it is possible to observe them, but use the full width of the margins.  Do not forget the final point in each text at the foot of the figure.

 Line 393 a 411 If the paragraph is too long, help readers enjoy reading it.

Use the dot appropriately in each paragraph.

 Figure 5. Carbon sequestration of mariculture shellfish in China during 2010-2020. DOT

Figure 7. (a) Total carbon sequestration of mariculture shellfish and seaweeds in China from 2010 to 2020; (b) Total carbon sequestration in 2010 and 2020 and average yearly growth rate of each. Dot

province. Dot

 Note 7. DISCUSSION

Recommendations

For discussion of the results:

1.-Begin by presenting the answer to the main question stated in the introduction?

2.-Does it deduce applications or implications of your answer?

3.-Does it highlight the novelty of the work by explaining what the conclusions reached add to existing knowledge?

4.-Do you claim priority if appropriate?

5.-Do you explain why the answer follows from the results, why it is reasonable, and how it fits within existing knowledge?

6.-Do you use scientific hypotheses rigorously?

7.-Do you not reiterate the results?

8.-Is the manuscript clear, relevant to the field, and presented in a well-structured manner?

9.-These are questions for your reflection and support.

The discussion is appropriate but should add empirical evidence.

4.1. Analysis of mariculture carbon sink capacity

Eliminate the word analysis, since all work is analyzed. Now the section is called discussion, the authors will try with arguments in the evidence to compare their findings. And explain them based on the evidence.

Figura 8. Verificación del secuestro de carbono de biomasa en diferentes especies de maricultura. Punto

Los años en el gráfico deberían mejorarse.

Combina nombres comunes y nombres científicos.

Una única referencia [50] para discutir el gráfico y la sección de forma muy limitada. Debería ser mejorado.

4.2. Análisis de la capacidad de sumidero de carbono de la maricultura

Eliminar la palabra análisis.

Línea 444 a 510. Misma recomendación para la longitud del párrafo.

Figura 11. (a) Contribución del factor de influencia al cambio del sumidero de carbono en la dimensión temporal; (b) Contribución del factor de influencia al cambio del sumidero de carbono en la dimensión espacial. Punto.

 Las siglas STF, EFF, SCF deben indicar al pie de los gráficos lo que significan, recuerde que esta revista puede ser leída por expertos en la materia o personas ajenas al campo del conocimiento.

Unifique el tamaño de los números (años), no utilice negrita.

En este apartado no hay ninguna referencia. Debería mejorarse, recomiendo a los autores investigar la evidencia empírica disponible para una discusión correcta.

 4.3. Mejorar eficazmente el sumidero de carbono de la maricultura en China

Esta sección no es propiamente una discusión, ya que esto es lo que proponen los autores, puedes ubicarla como:

5. Mejorar eficazmente el sumidero de carbono de la maricultura en China

 NOTA 7. CONCLUSIONES

Recomendación para conclusiones:

1.-¿Es el aporte original?

2.-Grado de vinculación a los objetivos.

3.-Grado de integración del marco teórico y de aplicación.

4.-Discusión suscitada respecto de los resultados obtenidos.

5.-Derivación de procesos normativos o explicativos sobre la realidad.

6.-Aclaración de los límites del estudio y propuestas de nuevos estudios.

7.-Son preguntas para la reflexión y el apoyo.

 Responder a las preguntas de las recomendaciones y reafirmar sus conclusiones.

Las conclusiones que proponen contienen algunos elementos para dar respuesta a los objetivos de la investigación, recuerde las variables de estudio.

¿Qué concluyen los autores de la estimación realizada y sus factores influyentes?

¿Qué pueden concluir de su modelo?

Las referencias generalmente no se incluyen en las conclusiones.

Esta sección es original, es la culminación de su trabajo.

¿Qué pueden concluir de su modelo?

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Mariculture carbon sinks in China: assessment and its influencing factors

Comments and suggestions

The Chinese references, very numerous (28/37), are clearly relevant. International literature would benefit from knowing them better and quoting them. However, in many cases the manuscript should cite additional references. See example hereafter.

Lines 45-46. ‘Carbon sequestration through marine ecosystems has also become a popular field of carbon sink research in recent years[4]’. The authors cite only one reference, and it concerns mariculture. Many references relate to natural ecosystems, such as mangroves and seagrass meadows, and should be cited. See e.g.:

Cuellar-Martinez T., Ruiz-Fernández A.C., Sanchez-Cabeza J.A., Pérez-Bernal L., López-Mendoza P.G., Carnero-Bravo V., Agraz-Hernández C.M., Van Tussenbroek B.I., Sandoval-Gil J., Cardoso-Mohedano J.G., Vásquez-Molina Y., Aldana-Gutiérrez G., 2020.  Temporal records of organic carbon stocks and burial rates in Mexican blue carbon coastal ecosystems through the Anthropocene. Global and Planetary Change, 192 (103215): 1-15.

Monnier B., Pergent G., Mateo M.Á., Clabaut P., Pergent-Martini C., 2022. Quantification of blue carbon stocks associated with Posidonia oceanica seagrass meadows in Corsica (NW Mediterranean). Science of the Total Environment, 838 (155864): 1-14.

The authors should indicate the species names of oysters, mussels, scallop, clams, blood clam, razor clam, kelp (a customary term which includes many brown seaweed genera, including wakame), wakame, nori and Gracilaria. Why does the order in which these taxa are listed change from one table or figure to another? E.g. kelp-wakame-Gracilaria-nori (table 1) and kelp-wakame-nori-Gracilaria (Table 4). E.g. oyster-mussel-scallop-clam (Fig. 9), clam-scallop-oyster-mussel-blood clam-razor clam (Table2), scallop-oyster-clam (Table 3) and oyster-blood clam-mussel-scallop-clam-razor clam (Table 4).

The authors seem to use ‘seaweeds’, ‘macroalgae’ and even ‘algae’ (e.g. Fig. 1) as synonyms. It would be good to specify in the introduction that macroalgae and seaweeds, used as synonyms, correspond to multicellular photosynthetic organisms, a polyphyletic group without taxonomic value. Please choose a term (e.g. seaweeds); avoid the term ‘algae’ (Fig. 1).

In chapter 1 (introduction), the notion of removable carbon sink (or fishery carbon sink) and the dilemma of shellfish carbon fixation via calcification (source or sink?) are well described. However, the distinction between short-term sequestration (a few months or years) in short-lived organisms (e.g. macroalgae and molluscans), and long-term sequestration (centuries to millennia) in sediment should be addressed. This is the case for mangroves, certain seagrasses (Posidonia and Thalassia) and coastal lagoons. Long-term sequestration is only mentioned through the recalcitrant dissolved organic carbon (RDOC). It also appears in the results section (e.g. line 348). Short-term vs. long-term sequestration should also be addressed in the abstract.

A reflection on the concept of a removable carbon sink would be interesting: once consumed by humans (shellfish, wakame, nori), or industrially processed (kelp, Gracilaria), the carbon returns to the atmosphere. Isn't the sink very short-termed?

The number of figures is very high. I'm not sure they are all useful. it would be better to choose those that best support the conclusions.

Line 130. Chinese Ministry.

Line 140. ‘The main species of mariculture seaweeds include kelp, wakame, nori, and gracilaria’. Please specify Latin names (e.g. Undaria pinnatifida for wakame).

Line 141. ‘four species’: wakame (Undaria pinnatifida) and kelp (Saccharina japonica?) correspond to species, but what about nori and gracilaria? Please do not use the term of kelp: kelp is a very general customary term for many large brown seaweeds; wakame belongs to kelp!

Line 143 (and the whole manuscript). ‘weight’? No: mass. The SI unit for weight is the newton (N), while the SI unit for mass is the kilogram (kg). Obviously, you mean mass!

Line 153. Fishery Statistical Yearbook: reference, please.

Table 2. ‘varieties’ à ‘taxa’. Please capitalize the first letter of ‘blood clam’ and ‘razor clam’.

Line 178. a and b.

Table 3. Please give the same number of decimals in a given column. 1.79 does not means 1.790 but ‘between 1.785 and 1.794.

Line 223. ‘structure factor (SSF), efficiency factor (SEF), and scale factor (SMF)’: why structure factor ‘acronym is SSF? Efficiency factor SEF? Scale factor, SMF?

Line 234. Variety? Rather ‘taxon’.

Figure 2. algae à seaweeds (or macroalgae: thank you for choosing).

Figure 2. The authors should indicate that the scale (left side) concerns either shellfish OR seaweeds, while the right side’ scale applies to shellfish AND seaweeds.

Line 307. 1000 à 1,000.

Line 325. species à taxa.

Figure 4b. Algae à seaweeds (or macroalgae: thanks for choosing).

Line 327. Species à taxa.

Figure 11. Algae à seaweeds (or macroalgae: thanks for choosing).

Line 476. 3060t à 3,060 t

Line 546. ‘many countries’: which ones?

Conclusions

The submitted article is interesting. It concerns a vast geographical area, and several taxa, so that its scope is not just anecdotal and local, but general. It therefore deserves to be published.

However, it contains too many errors in form. In addition, reflection on carbon sinks should be more critical, in particular with the distinction between very short-term (can we really speak of carbon sinks?) and long-term (real carbon sinks?).

For these reasons, I suggest accepting this article with major revision.

Reviewer 2 Report

The authors present an overview of the cases, events and biogeographic aspects of HAB. In general it is a good review, in the majority of the topics, however in what is related to cases and events it is limited to making an anecdotal description, it is suggested that the authors complement these sections with more numerical information and statistical data of health services in both the Philippines and Malaysia