Variations in CO₂ and CH₄ Exchange in Response to Multiple Biophysical Factors from a Mangrove Wetland Park in Southeastern China

Round 1

Reviewer 1 Report

Ever since joined Ramsar Convention 3020 years ago, China has made a lot of efforts for wetland conservation and restoration. Compared with other wetland ecosystems, there are less EC measurements in mangroves, although their carbon sequestration abilities are larger. Now the authors brought us with an exciting news that the 14-year-old mangroves have become a CO₂ sink, having potential to sequester more carbon in the future. Despite the benefit of CO₂ sequestration, the authors also cautioned the negative impacts of increasing CH₄ during mangrove restoration. I have only minor comments for this well-prepared work.

(1)   I noticed that the tower was adjusted from 5 m to 10 m for some reason (section 2.2). The authors also attributed the change from carbon source to carbon sink to the changes in sensors’ footprint. I wonder except the mangroves and open waters, is there any other ecosystems in the footprint? Do they have impacts on the carbon sources and sinks?

(2)   Figure 4d showed strong dependence of CH4 fluxes on air temperature. Does this relation also apply in other wetland areas?

(3)   In Line 297–299 I did not find soil salinity (should be ‘s’ as defined in the caption of Figure 2?) as a variable in Figure 4d.

(4)   Salinity is an important influence factor, especially on CH4 emissions. Why its relative importance is not shown in the paper? Some discussion is needed about this important influence in mangroves.

(5)   This study focused on a mangrove park which is special among the present research. But it also brought confused analysis about the source/sink, since the ecosystems are more complex than the natural ecosystems. I suggest the authors to give more experiments to separate the RE and CH4 emissions between mangroves and open waters, which could make a more clear analysis about the restored mangroves. This is a necessary future need which should be added in the last paragraph.

Author Response

Thanks to the reviewer’s constructive and helpful comments. We have significantly revised the manuscript based on the reviewers’ comments, and we believe the manuscript has been largely improved as a result. The reviewer’s comments are addressed point-by-point and documented in the attached file. A "tracked changes" version is also included in the submission for comparison.

Author Response File: Author Response.docx

Reviewer 2 Report

I appreciate the invitation to review the manuscript entitled “Long-term variations in CO2 and CH4 exchange in response to multiple biophysical factors from a mangrove wetland park in southeastern China”, the work is very important for the study of CO2 and CH4 cycles. The text itself is well organized. However, I note a few points:

1. On line 40, suggestion to replace “On the other hand” with “Furthermore”;

2. The figures are a little difficult to interpret. Check the possibility of improving their quality;

3. The acronym RE at times is Re (lines 263, 301, 318, ...), standardize;

4. Check, on line 282, the abbreviation RF;

5. On line 283, check the indication of the figure, mentioning Fig. 4f, however, there is only a,b,c,d in Figure 4;

6. In line 326, the abbreviation GHG is mentioned without prior reference to its meaning.

Author Response

Thanks to the reviewer’s constructive and helpful comments. We have significantly revised the manuscript based on the reviewer’s comments, and we believe the manuscript has been largely improved as a result. The reviewer’s comments are addressed point-by-point and documented in the attached file. A "tracked changes" version is also included in the submission for comparison.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Author,

The review, titled "Long-term Variations in CO₂ and CH₄ Exchange in Response to Multiple Biophysical Factors from a Mangrove Wetland Park in Southeastern China," is a very interesting study. But it has some minor modifications, as mentioned below:

· Line number 22: use CO₂ instead of CO2.

· On lines 45–54, the sentences are not connected to each other, so please correct them by mentioning the benefits of mangroves.

· Line number 111: Add the details of water sample collection.

· Line 133, place a space in between ‘night time," and correct all

· Should mention the time period during the study, it’s just confusing.

· Figure 2, is not precise. Please add a clear one.

· Table 1: Add the expansions of every driver and fluxes, which is also confusing.

· Line number 163-253, why have you not added any discussion part in between, included the same, or justified it?

· Line 263: instead of "Re," use "RE."

· Add a meaningful conclusion.

Author Response

Thanks to the reviewer’s constructive and helpful comments. We have significantly revised the manuscript based on the reviewer’s comments, and we believe the manuscript has been largely improved as a result. The reviewer’s comments are addressed point-by-point and documented in the attached file. A "tracked changes" version is also included in the submission for comparison.

Author Response File: Author Response.docx

Reviewer 4 Report

The research of this article is scientific significance, but the manuscript should be revised for publishing：

1. Line 114 to 120 ought to rewrite to make them more clearer.

2. The sentence “of the 5-m tower ranged from 100–200”in Line 123 is lack of data unit.

3.The charts are not clear such as figure 2

4. The figure in Line 255 is fig. 3 not 2.

5. The manuscript should be checked carefully overall.

6. The author need explain how to avoid the effect of different flux tower height on the results in the experiment.

Author Response

Thanks to the reviewer’s constructive and helpful comments. We have significantly revised the manuscript based on the reviewer’s comments, and we believe the manuscript has been largely improved as a result. The reviewer’s comments are addressed point-by-point and documented in the attached file. A "tracked changes" version is also included in the submission for comparison.

Author Response File: Author Response.docx