Seasonal Dynamics and Trophic Impact of Mesozooplankton in the Shannon River Estuary System, Ireland

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents a study performed 45 years ago in the Shannon estuary and as the authors state in the introduction it could be useful only for detecting subsequent changes. No important findings are presented regarding the annual cycle of mesozooplankton in a temperate estuary. Comparison of the results obtained at three stations is not clearly discussed, as well as of the environmental parameters, especially those issued from the PCA analysis. Similarly, comparison of the results in the Shannon estuary with those obtained in other estuaries, are poorly discussed and concerns mostly taxa composition. No comparison is attempted for the annual cycle, the diversity indices, the grazing impact.

The estimation of the mesozooplankton  grazing impact could be considered as an interesting point, though there are several restrictions for the applied method (already mentioned by the authors). On the other hand, it is not clear which is could be the impact of the equinox and solstice on mesozooplankton, as the authors considered their inclusion in the PCA analysis as an innovation. Which could be the role of the celestial parameters on mesozooplankton ecology? This is necessary, since it is the first time that these parameters are considered.

 The word “mesozooplankton” is more appropriate than “mesoplankton”, since the study concerns exclusively zooplankters. Thus, mesoplankton should be replaced in the entire document.

An important problem is the use of the term “clearance rate” for the estimation of the grazing impact of mesozooplankters on their prey. In the literature clearance rate refers to the volume of water a zooplankter “clears” of prey per unit of time and it is expressed in L.ind-1.d-1. But the grazing impact on the preys that the authors wanted to estimate is obtained by multiplication of the clearance rate with the abundance of the zooplankter. Thus, a confusion is issued from the use of “clearance rate” for both processes, the clearance rate of water by the zooplankter and the grazing impact of the zooplankter. This should be clarified and corrected in the entire document.

Results and discussion are presented in many and small subchapters e.g. a subchapter for a single taxon.The rank of presentation is strange e.g. diversity and PCA results are presented before the results on community composition, thus the reader could be confused. In contrast, the grazing impact is presented in the first sub-chapter of the discussion, followed by the community composition and the diversity. In addition, there are sentences in the results which should be moved in the discussion, and vice-versa. There are several editing mistakes in the manuscript and two tables are missing from the manuscript. Few references are not relevant to the text, while there are sentences which should be supported by a reference

Overall, the manuscript is roughly written and it should be deeply revised before being accepted. Detailed comments are given in the attached pdf file. 

Comments for author File: Comments.pdf

Author Response

lease find alaso a new R1 manuscript, with the references cited inn the text, and an another file, with the rference cited as number.

Reply to Reviewer 1.

Over all report:

Reviewer The manuscript presents a study performed 45 years ago in the Shannon estuary and as the authors state in the introduction it could be useful only for detecting subsequent changes. No important findings are presented regarding the annual cycle of mesozooplankton in a temperate estuary. Comparison of the results obtained at three stations is not clearly discussed, as well as of the environmental parameters, especially those issued from the PCA analysis. Similarly, comparison of the results in the Shannon estuary with those obtained in other estuaries, are poorly discussed and concerns mostly taxa composition. No comparison is attempted for the annual cycle, the diversity indices, the grazing impact.

Reply Thank you for these comments. Contrary to Rev1, we believe tat a very important finding is tthat the trophic impact was dominated by mysids, while most European estuaries have been found to be dominated by copepods, or else the mysids are not considered in detail. An exception is work done in the Gronde (David, 2006; David et al., 2006). Rev 1 remarks that comparisons of the results obtained at the three stations is not clearly discussed, but we feel that this comparison was discussed adequately, particularly in relation to the PCA analysis. Rev 1 also remarks that the results in the Shannon estuary are poorly discussed in relation to those from other estuaries. In fact, we found that the different estuaries reported gave very different annual cycles of the different taxa, and are therefore difficult to compare meaningfully. The same reply is made in relation to the diversity indices and the grazing impact. The diversity indices vary different ly for different estuaries, except that they are generally highest in summer, but this seems too banal to discuss.

Reviewer The estimation of the mesozooplankton  grazing impact could be considered as an interesting point, though there are several restrictions for the applied method (already mentioned by the authors). On the other hand, it is not clear which is could be the impact of the equinox and solstice on mesozooplankton, as the authors considered their inclusion in the PCA analysis as an innovation. Which could be the role of the celestial parameters on mesozooplankton ecology? This is necessary, since it is the first time that these parameters are considered.

Reply We thank the reviewer for these insightful comments. With respect to the reviewer’s comment that it is not clear which could be the impact of the equinox and solstice on mesozooplankton, as we stated in our lines 191 to 193, our spirit of statistical analysis is descriptive, not inferential, following Jolliffe & Cadima (2016) and Kassambara & Mundt (2000). However, since our use of celestial variables is an innovation, we follow the reviewer’s suggestion and add a few more words about this In the legend to Fig. 6, We have explained better the relationship of the other variables to the celestial variables

Reviewer The word “mesozooplankton” is more appropriate than “mesoplankton”, since the study concerns exclusively zooplankters. Thus, mesoplankton should be replaced in the entire document.

Reply Thank you! We have changed “mesoplankton “ to “mesozooplankton” throughout the manuscript.

Reviewer An important problem is the use of the term “clearance rate” for the estimation of the grazing impact of mesozooplankters on their prey. In the literature clearance rate refers to the volume of water a zooplankter “clears” of prey per unit of time and it is expressed in L.ind-1.d-1. But the grazing impact on the preys that the authors wanted to estimate is obtained by multiplication of the clearance rate with the abundance of the zooplankter. Thus, a confusion is issued from the use of “clearance rate” for both processes, the clearance rate of water by the zooplankter and the grazing impact of the zooplankter. This should be clarified and corrected in the entire document.

Reply Thank you for helping us with this important point of definition. We have carefully distinguished “grazing rate” from “clearance rate “ throughout the manuscript. Furthermore, in section 3,4, we have added, “The term, clearance rate, is used is used to mean clearance per individual per time unit, whime “grazing rate” (or “trophic impact” means the volume grazed per time unit by the population of a given taxon. “Grazing rate” = “clearance rate ₓ abundance. “

Reviewer Results and discussion are presented in many and small subchapters e.g. a subchapter for a single taxon.The rank of presentation is strange e.g. diversity and PCA results are presented before the results on community composition, thus the reader could be confused. In contrast, the grazing impact is presented in the first sub-chapter of the discussion, followed by the community composition and the diversity. In addition, there are sentences in the results which should be moved in the discussion, and vice-versa. There are several editing mistakes in the manuscript and two tables are missing from the manuscript. Few references are not relevant to the text, while there are sentences which should be supported by a reference

Reply Thank you for these detailed comments and suggestions.

1. In the Results section, we have moved the diversity and PCA results to follow the Community Composition results. DONE

2. The Grazing Impact subchapter is now at the end of the Results section DONE.

3. We have paid attention to moving sentences in the Results section to the Discussion and vice versa, where required. DO THIS

4. Sorry about the editing mistakes. We have tried to correct all these . Apologiesforf any remain. DO THIS

5. Sorry about the problem with the tables. I have now inserted Table 8, which replaces Table 9. Table 9 no longer exists.

Reviewer Overall, the manuscript is roughly written and it should be deeply revised before being accepted. Detailed comments are given in the attached pdf file. 

Reply Thank you. We will pay attention to the reviewer’s detailed comments on the manuscript and polish the style.

Reviewer 2 Report

Comments and Suggestions for Authors

This research provided precious data of mesozooplankton community in 1979-1980, which would be a baseline for comparisons with the current conditions of Shannon River Estuary. However, the aim of this research, methods of analyses, and presentation of results have to be drastically improved before it can be published.

Aims of this study

1. It is interesting that you analyzed the samples from over 40 years ago instead of new survey data. I agree that these old samples can be treated as the baseline of ecological analyses in this area, but you need to point out this significance in the introduction more strongly.
2. You tried to estimate the clearance rates of dominant mesozooplankton and their biodiversity, which may contribute to the understanding of trophic transfer in this area. However, you did not explain why you calculate these in the introduction. Please state clearly the motivation why you did these analyses.

Methods and Analyses  

1. I do not agree that mixing the environmental factors and mesozooplankton abundances in PCA is an innovative and appropriate analysis. The environmental factors included (temperature, salinity, seasonality, turbidity) here are mostly not influenced by mesozooplankton or nanoplankton--instead, they very likely drive the dynamics of plankton. I would use RDA instead to investigate which environmental factors may affect mesozooplankton abundance. This makes more sense.
2. If you want to consider the seasonality, or want to explore the relationship between mesozooplankton community compositions and environmental conditions excluding the periodic effect of seasonality (which I would recommend), it is better to use GAM to model the seasonal effect and partial out the seasonality of the environmental and mesozooplankton data before doing the analyses you want to do (regressions, PCA, and etc).

Presentation of the results

1. I don't understand what the numbers in the PCA biplots mean. Are they the station names? Why are there 1_1, 3_1, 9_3 and etc while on the map there are only Stn 1, 3, 4?
2. What do the arrows and colors mean in the PCA biplots?
3. Figure 6 mixed the data of environmental and biological factors, which made the figure difficult to read and understand. Divide this huge figure at least to two figures showing  "environmental conditions" and "major zooplankton abundances".  

Comments on the Quality of English Language

The English language is not satisfactory. There are many strange typos and misuses of the punctuation marks, which makes reading this manuscript annoying. Because there are no line numbers in the manuscript, I have difficulty listing these problems. Please check the words thoroughly before submission. 

Author Response

eply to Reviewer 2

This research provided precious data of mesozooplankton community in 1979-1980, which would be a baseline for comparisons with the current conditions of Shannon River Estuary. However, the aim of this research, methods of analyses, and presentation of results have to be drastically improved before it can be published.

Reply

Thank you, particulalry for your recognition of the presented data as “precious”.

Aims of this study

1. It is interesting that you analyzed the samples from over 40 years ago instead of new survey data. I agree that these old samples can be treated as the baseline of ecological analyses in this area, but you need to point out this significance in the introduction more strongly.

2. You tried to estimate the clearance rates of dominant mesozooplankton and their biodiversity, which may contribute to the understanding of trophic transfer in this area. However, you did not explain why you calculate these in the introduction. Please state clearly the motivation why you did these analyses.

Reply

1, Concerning Rev #2’s first concern, above, in the Introduction, we have included the sentence, “Concern about the possible ipacts of the plant and its attendant extra shipping promoted fuding of ecological baseline surveys of the plankton and intertidal biota, which were carriedout _from 1978 980 ​[O'Sullivan, 1983; O'Sullivan, 1984; Jenkinson, 1985; Jenkinson, 1990]". DONE

Thank you. We have now explained in the Introduction why that we calculated clearance rates (now called grazing rates, after comment by Rev #1) of the dominant mesozooplankton in order to provide understanding of trophic impact on the plankton community by the major mesozooplankton taxa. Our results indicated that mysids were the dominant controlling taxon. DONE

Methods and Analyses  

1. I do not agree that mixing the environmental factors and mesozooplankton abundances in PCA is an innovative and appropriate analysis. The environmental factors included (temperature, salinity, seasonality, turbidity) here are mostly not influenced by mesozooplankton or nanoplankton--instead, they very likely drive the dynamics of plankton. I would use RDA instead to investigate which environmental factors may affect mesozooplankton abundance. This makes more sense.

   Reply

   Our aim is not to show which factors were driving the dynamics of the plankton. While we included factors, inclusing temperature, salinity and seasonality in the facotrial analysis, we suspect that that there are other drving factors that we could not measure, such as internal clocks of the mesozooplankton taxa, that meay play important roles as they interact among the different taxa. We prefer to follow the approach of of using statistical analysis, factorial analysis in the present case, as descriptive, not inferential tools, following Jolliffe & Cadima (2016) and Kassambara & Mundt (2000).

2. If you want to consider the seasonality, or want to explore the relationship between mesozooplankton community compositions and environmental conditions excluding the periodic effect of seasonality (which I would recommend), it is better to use GAM to model the seasonal effect and partial out the seasonality of the environmental and mesozooplankton data before doing the analyses you want to do (regressions, PCA, and etc).

Reply

With sincere thanks and respect, our aim was not explore the relationship between between the mesoplankton community and environmental parameters, excluding seasonal effects. A study to allow exclusion of seasonal effects. would have required a much more intensive sampling regime over a short period of time, The primary aim of the present study was show the annual distribution of mesozooplankton taxa in the study area. We believe we have succeed in doing this for the area and time frame investigated. Like all environmental studies, the present one was constrained by the human and fnding resources available.

Presentation of the results

1. I don't understand what the numbers in the PCA biplots mean. Are they the station names? Why are there 1_1, 3_1, 9_3 and etc while on the map there are only Stn 1, 3, 4?

2. What do the arrows and colors mean in the PCA biplots?

3. Figure 6 mixed the data of environmental and biological factors, which made the figure difficult to read and understand. Divide this huge figure at least to two figures showing  "environmental conditions" and "major zooplankton abundances".  

Reply

We are sorry that the reviewer did not understand the convention we used to refer to the different statuions, 1, 3 and 4 on each cruise, numbered from 1 to 9. We are sorry that this was not adequately explained. The reviewer thus, unfortunately, missed the rotation of the stations with the annual cycle in the factorial space defined by PCA facotors 1 and 3. In section 3.1, we have now givan the dates of the cruises and the station numbers . In the legend to Fig. 5 (now Fig. 6) we have summarized this information and explained the convention of how the stations are presented in the fgure DONE. . We have also also explained the signifgicance of the attow colours in these biplots. We thank thereviewer for pointing out this omission. DONE.

 

Concerning Fig. 6,we do not wish to convey that there is a hard division between “driver” and “driven” variables. Even though some variables, such as temperature, salinity or seasonality cannot be “driven variables, other variables may be “driven” and “drivers”. Factotrialnabalyses also generally incorporate no time lag in their correlations, whereas there is always a time lag between “driver” and “drven” variables, sometimes infintessimal, other tiumes of seconds to years or more. We wish our anlyses to escape from the staightjacket of assuming instantaneous cause-and-effect relationshoips between the different variables presented.

 

Comments on the Quality of English Language

The English language is not satisfactory. There are many strange typos and misuses of the punctuation marks, which makes reading this manuscript annoying. Because there are no line numbers in the manuscript, I have difficulty listing these problems. Please check the words thoroughly before submission. 

Reply

Thank you. We have carefully checked the English language and punctuation, and I take total responsibility for any mistakes that remain. DONE.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors revised their manuscript following most of the suggestions. However, there are still some points to be corrected for the improvement of the manuscript. Namely, there are sentences in the results which discuss the obtained reuslts. On the opposite, many sentences in the discussion present results (e.g. grazing rates) with no significant discussion. Detailed comments are given in the attached file.

Comments for author File: Comments.pdf

Author Response

Reviewer 1

 

Comments and Suggestions for Authors

The authors revised their manuscript following most of the suggestions. However, there are still some points to be corrected for the improvement of the manuscript. Namely, there are sentences in the results which discuss the obtained results. On the opposite, many sentences in the discussion present results (e.g. grazing rates) with no significant discussion. Detailed comments are given in the attached file.

 

 

pdf

Comments on the revised manuscript

Dynamics and trophic impact of mesoplankton in the Shannon River Estuary

system, Ireland. By Ian R. Jenkinson and Tom H. Ryan

The authors revised their manuscript following most of the suggestions. However,

there are still some points to be corrected for the improvement of the manuscript.

Mesoplankton was not replaced by mesozooplankton in some sentences e.g. L.40,

 

R I have a problem in the line numbers don’t seem to match the copy I have.

 

67, 143

R Sorry I can’t find this

 

L. 56…. 1980

R DONE

 

L. 68, 185: parenthesis is missing

R I hope this was cleared up in my editing

 

L. 414 editing error

R I cools not find this

 

L.417 “4.3. Secchi disc water clarity and colour” and “4.3. Detritus volume fraction”.

It will be better to join the two subchapters in one e.g. 4.3 Clarity, colour and detritus

volume of the water.

R I have kept these two sections consecutive, as the colours likely to have been influenced also by the phytoplankton, especially during the red tide of Glenodinium foliaceum.

 

L.435 correct enumeration of “4.3. Total mesozooplankton”

R Many instances have been corrected to “mesozooplankton”.

 

L.645 to 650 should not be part of the Figure legend, but it should appear in the text

regarding PCA results

R The second part of the legend of Fig 6 has now been transferred to the text (Results).

 

L. 646, 647 “…to the upper left-hand quadrant in Fig. 1a (D1-D2), and that in Fig. 1B

R Thank you. This is corrected.

 

(D1-D3),”. Correct Fig 1a, Fig.1b to Fig.6a, Fig.6b

DONE

 

Table 1. “Abbreviations of variable shown in Figure 4…” Correct to: . “Abbreviations

of variable shown in Figure 6…”

R Thank you/ DONE

 

L478 “In the D1-D2b plane” delete b

R DONE

 

Table 3. Gazing rate

DONE

 

L.597-599 the sentences should be moved in the discussion

R Sorry, I think this information on “dominant and noteworthy species should be kept together in one place.

 

Generally, results e.g. grazing rates, should not appear in the discussion, except for

comparison with other areas.

R Sorry, but in the Discussion, I think it’s OK to compare grazing rates exerted by different taxa.

 

L. 783-786: These are results, delete them. L.786-788: these comments should be

moved in the chapter 5.3 regarding Acartia.

R I have left this material all together, rather than creating a new heading in the Discussion.

 

As it was suggested in my previous report, the subchapter “Trophic structuring by the

mesozooplankton” should be together with the subchapter “Grazing impact of

mesozooplankton on the estuary ecosystem”, because both refer to the

zooplankters playing important grazing role on the ecosystem. To mention at which

station the grazing impact of mysids was highest. In addition, it is not necessary to

mention in detail the grazing rates of each group, which were presented in the

results. Namely:

 

L. 777-778 “Table 2 shows that trophic impact by P. pileus was confined to the

period from May to November. Mean annual grazing rates were 0.00, 0.08 and 0.75

L m-3 d-1 at stations 1, 3 and 4 respectively. P. pileus was not observed at station 1.”

The above are results. In the discussion you should mention that “the low grazing

rate values estimated in the present study imply that the trophic impact of P. pileus

is very low”.

R Sorry, I don’t agree that the grazing pressure of P. Pileus was very low (except at Station 1). Moreover, as it is carnivorous, it cannotbe directly compared with the herbivorous/detritivorous grazing pressure estimated for the other taxa. Furthermore, we have discussed the summer grazing pressure by P. Pileus in relation to the August minimum of copepods and mysids (now in 5.3.3.5.). So have not changed this

 

L. 788-789 “The year-round mean estimated grazing rates for all copepods combined

(except copepodites and nauplii) was 0.08, 0.35 and 1.1 L m-3 d-1 et stations 1, 3 and

4 respectively (Table 6)”: these are results. The sentence should be written “The

year-round mean estimated grazing rates of all copepods (except copepodites and

nauplii) were low, nearly two orders of magnitude less than that of the mysids”.

R Thank you! I have adopted this suggestion.

 

L.792-793 eliminate the numbers and write that mysids grazing rates were the

highest of all zooplankters and mention at which station it was highest. Here you

should mention that the trophic impact was dominated by mysids, that this finding is

very important since while most European estuaries have been found to be

dominated by copepods, an exception is work done in the Gironde (David, 2006;

David et al., 2006)”, as you wrote in your reply to the first comments.

 

R Thank you very much. I have added the following sentence to the end of the Discussion, for emphasis:”Mesopodopsis dominated the trophic impact in the Shannon estuary system. This is in contrast to most European estuaries, except the Gironde, where trophic impact has been found to be dominated by copepods.” The references for this statement are given elsewhere in the paper,.

 

L.832 Acartia bifilosa is a “companion species” to E. affinis in many European

estuaries. Add references.

R Sorry, I couldn’t find the reference. Changes to “Acartia bifilosa occurs together with...”

 

L. 839-847 : were these comments made by Vaupel-Klein and Weber or by other

authors or by the authors of this study? Clarify.

R I quoted directly from the authors’ work.

 

In their reply to my previous comments, the authors mentioned “we found that the

different estuaries reported gave very different annual cycles of the different taxa,

and are therefore difficult to compare meaningfully. The same reply is made in

relation to the diversity indices and the grazing impact. The diversity indices vary

different ly for different estuaries, except that they are generally highest in summer,

but this seems too banal to discuss.” In my opinion, the discussion of the obtained

results in comparison with other estuaries is crucial in a study describing the

zooplankton composition and its seasonal dynamics. The authors could focus in the

comparison within estuaries at the same latitude and with same salinity, which

would be less difficult and more meaningful. Discussion regarding diversity is well

presented.

R Thank you. Comments I made in a reply, I would find difficult to justify and support in a peer-reviewed publication. Maybe someone needs to write a review paper on inter-estuary comparisons.

I cannot do this now. Perhaps the reviewer could!

 

The subchapter 5.5. “ The factorial analysis” presents the results of PCA and

therefore it should be joined with the relevant chapter in the results (4.6). In a

chapter entitled “Mesozooplankton dynamics and environmental factors” the results

obtained by PCA could be discussed. Namely, a) the distinction of Station 1- Salinity

was a clear key variable in setting Station 1 apart. b) annual variability was clearly

shown by PCA, related to celestial variables, temperature and salinity.c) all three

stations showed rotational movement over the year, and the physical, chemical and

biological variable showed positions corresponding to their seasonal characteristics over the e year.

 

R Thank you. I have added your suggestions for 2 and c to make a new paragraph in section 5.3. Item a was already covered in the preceding paragraph of this section.

 

 

Conclusions

Generally, results e.g. grazing rates, should not appear in the conclusions.

L.1027-1032 these are results!!! Only the sentence “all three stations showed

rotational movement over the year, and the physical, chemical and biological

variable showed positions corresponding to their seasonal characteristics over the

year.”, can be included in the conclusions.

R I have deleted the paragraph with the numerical data. And added a sentence about the rotation of the stations. Very nice. Thank you!

 

L 1036-1037 “The copepod fauna overall was dominated by Eurytemora affinis,

Acartia bifilosa and A. discaudata, as well as the somewhat less abundant A. clausi.

This fauna is typical of many temperate estuaries” This sentence or a rephrased one

should be included in the discussion (5.3.1) with references for other temperate

estuaries

L.1040-1047 Do not mention the numbers of grazing rate, just the taxon having the

highest rate and then the role of carnivorous grazing.

R I have deleted this paragraph.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This current version is significantly improved. Though I still do not quite agree that including celestial variables into PCA is innovative, but including these variables does provide the seasonality information in the PCA biplot. With limited samplings, this would be the most acceptable analysis can be done. Since these biplots are informative, PCA should be emphasized in the Results. I suggest to move Fig. 6 to Fig. 4, and put original Fig. 4 and Lines 412-612 to Appendix. Just described roughly the environment condition and what the dominant species are and ask readers to check the appendix to see the detail seasonality of these parameters.

Specific comments:

Lines 107-111: I am not sure if it is the problem of punctuation marks, it is difficult to understand this sentence. Would you check and rephrase it?

Line 208: this subtitle is not necessary. These paragraphs can be simply included in the previous PCA section.

Line 264: Should be "Pleurobrachia pileus". Also, species names should be Italic in the subtitles.

Lines 393-394: This sentence is redundant.

Line 408: The highest salinity seemed to be in April in Fig. 3.

Fig. 3, 4, 5: I know you want to show the annual cycle from January to December, but it is really weird to move 1980 data ahead of 1979. I prefer showing the original time series, and mark the seasons on the figure. I believe that readers can find the seasonality.

Lines 437 and others: You used "ind" for abbreviation of "individuals" in the previous paragraphs, not "indiv". It is better to use the same abbreviation throughout the manuscript.

Line 453: Now the true jelly fish, siphonophores, hydra are in the phylum Cnidaria. Use "cnidarians" is more appropriate.   

Comments on the Quality of English Language

There are still typos (e.g. Line 976 "graphicl" should be "graphical"; Line 723 "E." should be deleted) and strange use of punctuation marks (e.g. Line 350 An additional ")" in front of [47]). Please check and correct them carefully before publication. They may not influence the meaning of the sentences but cause difficulty in reading (and annoying).

Author Response

Comments and Suggestions for Authors

This current version is significantly improved. Though I still do not quite agree that including celestial variables into PCA is innovative, but including these variables does provide the seasonality information in the PCA biplot. With limited samplings, this would be the most acceptable analysis can be done. Since these biplots are informative, PCA should be emphasized in the Results. I suggest to move Fig. 6 to Fig. 4, and put original Fig. 4 and Lines 412-612 to Appendix. Just described roughly the environment condition and what the dominant species are and ask readers to check the appendix to see the detail seasonality of these parameters.

R I thank the reviewer profusely, and appreciate it that they see the PCA as an appropriate factorial treatment given the size of the dataset.

1. I have added a section (4.6.) explaining the PCA in the Results, partly replacing the long figure legend

2. Fig. 6 to FIG. 4 . DONE

3. There seems to be a difference between the reviewers’ line numbers and my own, but I presume this refers to “L 412-612 to Appendix. (4.4. Dominant and noteworthy zooplankton”. I believe tie information is crucial for future investigators, so I propose it remains in the body of the paper, but UI will abide by the editor’s decision.

Specific comments:

Lines 107-111: I am not sure if it is the problem of punctuation marks, it is difficult to understand this sentence. Would you check and rephrase it?

R I can’t see where this is, but I hope my “polishing” effort has resolved this problem.

Line 208: this subtitle is not necessary. These paragraphs can be simply included in the previous PCA section.

R I hope this has been resolved by the “polishing”. I will follow the Idiot’s instructions regarding headings.

Line 264: Should be "Pleurobrachia pileus". Also, species names should be Italic in the subtitles.

R The polishing resolved many errors in italicizing etc. I hope this is now OK.

Lines 393-394: This sentence is redundant.

R Sorry, I can’t see where this is.

Line 408: The highest salinity seemed to be in April in Fig. 3.

R I think you mean May 1980. Salinity was much higher at all stations in May 1980 than in May 1979.

Fig. 3, 4, 5: I know you want to show the annual cycle from January to December, but it is really weird to move 1980 data ahead of 1979. I prefer showing the original time series, and mark the seasons on the figure. I believe that readers can find the seasonality.

R I understand, and believe there are advantages to both methods. I prefer to not having to redraw all the graphs, when the advantage of doing so is not clear. However, I will comply with the editors’ decision.

Lines 437 and others: You used "ind" for abbreviation of "individuals" in the previous paragraphs, not "indiv". It is better to use the same abbreviation throughout the manuscript.

R If the editor requires, I will change “ind.” to “indiv.”

Line 453: Now the true jelly fish, siphonophores, hydra are in the phylum Cnidaria. Use "cnidarians" is more appropriate.   

R We already used the term “planktonic cnidaria”, not” jelly-fish”

 

Comments on the Quality of English Language

There are still typos (e.g. Line 976 "graphicl" should be "graphical"; Line 723 "E." should be deleted) and strange use of punctuation marks (e.g. Line 350 An additional ")" in front of [47]). Please check and correct them carefully before publication. They may not influence the meaning of the sentences but cause difficulty in reading (and annoying).

R. I hope the “polishing” has resolved all these issues.

 

Author Response File: Author Response.pdf