Benthic Invertebrates Abundance and Trophic Links in the Coastal Zone during Cladophora Blooms

Round 1

Reviewer 1 Report

accept for publication.

Author Response

Author thank reviewer for positive evaluation, text of manuscript was edited

Reviewer 2 Report

The manuscript entitled "benthic grazers abundance and trophic LINKS in the coastal zone during Cladophora blooms" studies the relation between benthic grazers, algae and stables isotopes in relation to blooms in the Neva estuary. The authors demonstrated how high amounts of algae are consumed by macroinvertebrates, in addition to manuscripts that have studied similar estuaries before.

The manuscript is well organized, and there is good field and laboratory work, my congratulations to the authors for this hard work. However my major concerns is in the methodology sections and the presentation of results. Authors do not sufficiently explain the methodology. Here it is not clear if sampling was during o after a bloom of Claodophora. Authors mention which statistical analyses were performed (e.g. ANOVA) in section 2.4. However, no significance analysis is presented in the results, tables or figures.

In the introduction, only studies of the alga Cladophora are mentioned, leading the reader to believe that only this alga and its impact on macroinvertebrates will be evaluated. However, in the methodology the authors mention that in addition to this alga, other algae will also be evaluated for their biomass and stable isotope analysis. Authors should mention then in introduction, the importance of these other algae.

In the methods section, authors should mention how they identified the macroinvertebrates, and how the functional feeding groups were assigned ( may be add FFG in supplementary Table).

Authors only show figures in the results section, however for a better understanding of the study, they should attach data tables, for example for figure 4.  In the results section, L193, authors mention that the biomass of drifting algae varied between 101 to 130 g/m2. However, where can we find this information in tables or figures?

In L200 The authors mention that the abundance/biomass was poor at sites 7 and 10 (Fig. 3). But if we look at Fig. 3 at station 6 it is also low, authors should mention this and discuss.

L200 and 210. Epitobrilus medius  and G. zaddachi, are not listed in supplementary Table. How is it possible that these species that authors name in the manuscript, but are not described in the taxa list?

L209-211. Species name in italic

L211. Why Bythinia spp? if only Bythinia tentaculata was identified?

L216. In supplementary table is listed as Teodoxus fluviatilis not, Theodoxus

L220-221. However, looking your Fig 4, the greatest biomass was founded in sites 1, 9 and 10. Not site 5. It seems that there is an error in interpretation

L231. why you take samples only in site 2 and 4 to stables isotopes? It is not mentioned in methods

The discussion section needs work. Authors should discuss the survival of amphipods, and the ecological status of the stations, which is presented in the results. Here it is not discussed because there is higher biomass of Cladophora at sites 1,2, 8, 9 and 10, which partially coincides with the higher abundances and biomass of meiofauna. These stations are the ones furthest outside the estuary. Thus, will the location of the sampling stations have any effect on macroinvertebrate composition, and this on algal predation? Authors only studied stable isotopes at stations 2 and 4, but what about other invertebrate species that did not appear at these sampling stations? Are they also feeding on algae after the bloom? Why was phosphorus higher in some sampling stations and not in others? What effect does this have on the results?These questions could help the discussion.

In the concluding section, the authors conclude that algae are an essential resource for grazers. In this sense, the authors mention in the introduction, that after bloom the algae decompose, and could cause negative effects on invertebrates. It is not clear from this study whether it was during or after a bloom. So, are grazers benefited or harmed by these blooms?

Minor comments:

L2. Benthic instead benthic

L21. Delete the ":" and the words "How to use this template".

L30. salinity from 0 to 7. PSU or ppt?

L86. been studied instead beenstudied 

Table 1. Salinity is expressed in PSU or ppt? Oxygen ml/l ? Is not mg/L?

L183. please add mg/L after 42 to 148.

Figure 2. Please add axis Y

Figure 6. Description. Cladophora and other plants. Only plants? and algae?

In supplementary Table, species name in italic.

Author Response

Authors tank reviewer to valuable comments and useful recommendations that helped improve first version of manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript entitled "benthic grazers abundance and trophic LINKS in the coastal zone during Cladophora blooms" describes trophic dynamics in the Neva Estuary during Cladophora blooms. Despite the theme being relevant to the advancement of understanding of trophic relationships in estuarine environments, the manuscript is not well written. Both the introduction and the discussion need a better development of the text, with the use of ecological theories and more recent and relevant references on the proposed theme. This should be verified. Please find below my specific comments.

1. Keywords

- Line (21): Delete the duplicated colon signal;

- Line (21-22): Delete the sentence “0. How to Use This Template”;

2. Introduction

- Citations must be numbered. Authors' names must not appear;

- Line (50): I didn't find "Gorbunova, Esyukova 2020" in the references;

- Line (52): I didn't find "Gubelit et al., 2016" in the references;

- Line (67): I didn't find "Peckol and Rivers 1995" in the references;

- Insert hypotheses/predictions that can be tested/expected with the work;

3. Materials and Methods

- Line (133): Change "Enviromental" to "Environmental";

- Line (176): Provide the citations/URL of the Past and STATISTICA software;

4. Results

- Figures 2-3: In the graphs, provide the names of the Y axes;

5. Discussion

- I found the discussion too short. I believe the work would benefit from a better exploitation of the results;

- In the first paragraph, summarize the results of the work;

- In the discussion, do not indicate the figures or tables;

- Line (277): I didn't find "Post 2002" in the references;

- Line (290): I didn't find "Choo et al. 2017" in the references;

6. References

I didn't find the following references: 

- Line (375): "Best...";

- Line (381): "Choo...";

- Line (387): "Dodds...";

- Line (394): "Fong...";

- Line (438): "Rivers...".

Author Response

Authors thank the Reviewer for evaluation and comments, according to Reviewer’s comments, the text was clarified and edited.

In Introduction and other parts of paper all citations were numbered and references were checked to be included all cited papers.

Reviewer pointed that hypotheses/predictions that can be tested/expected with the work should be added. See L/106-115: The main question of the work was to determine whether there is a positive contribution from the mass development of Cladophora for the coastal community, since in previous studies we did not find a clear answer to whether this autochthonous source of organic matter is used by local consumers. Or, the effect of the macroalgae bloom consists only in a negative impact through the deterioration of physical and chemical conditions leading to low biomass of coastal inhabitants as evidenced by numerous studies in various estuaries. The macroalgae biomass, composition, and abundance of macro- and meiobenthic invertebrates and their trophic relationships in the coastal community were investigated along costal line of the Neva estuary during summer macroalgae bloom.

Small mistakes were corrected.

Figures were improved and all axes were named.

We added more detailed discussion of results, this part was fully reconsidered.

All small mistakes were corrected.

Reviewer 4 Report

Manuscript Number: 2027189-peer-review-v1

Article Type: Article

Article title: Benthic grazers abundance and trophic LINKS in the coastal zone during Cladophora blooms

Authors: Nadezhda A. Berezina: Alexei V. Tiunov, Vasily A. Petukhov, Yulia I. Gubelit

The Paper deals with an interesting topic but of rather limited international importance. In my opinion, the methodology used was described in detail but requires some additional information. Unfortunately, sampling methods (frequency) in such a type of study is insufficient. Therefore I am not convinced that these results should be published. Some suggestions and comments are placed below, which I hope will help authors to improve their Manuscript.

1.      Title should start with the capital letter, please also check the font in the title “LINKS” The title is incorrectly constructed, in the Cladophora blooms instead of “during.”

2.      I regret the lack of hypotheses, I would suggest formulating the aims of the study into the form of one or two hypotheses, but from the results obtained ( and methodology used), I can only see the comparison between the results from one month of sampling.

3.      “The study aimed to determine present ecological conditions in the Neva estuary coastline: the macroalgae biomass, their contribution to the autochthonous benthic food web, and the possible influence of Cladophora blooms on composition and abundances of  macro- and meiobenthic grazers and their trophic relations.”- Authors wrote in study aims ".. ecological conditions.." but having the results from only one sample in July 2021 they only have results from one month, one point of time. The ecological conditions change in time and space, and therefore the ecological context of the study requires repetitive sampling.

4.      Methods: What kind of macroinvertebrate samples was it- is not clear from the text, were they quantitative samples? Other groups of organisms were sampled in the context of area unit, but how about macroinvertebrates, the second question is if such results were comparable. This part of the text needs to be supplemented.

5.      Methods: The samples were taken only in July 2021, unfortunately, I think that this is not enough to make significant and reliable results regarding the assessment of the situation, such studies should be repeated at least 3 times; otherwise, we only have basic preliminary results from one sampling. This is, in my opinion, not enough to be public in a scientific journal, and I have no conviction that they should be published. There are two options for authors, first- repeat their sampling and get more results, check if they are comparable and repeatable, or second change the title and highlight that study is a preliminary, a case study.

6.      Table 1  the salinity unit should be included in the table

7.      2.4 Statistics: “…. Mean value…” mean from which values if the sampling was done only in one month?

8.      3.2. Benthic community/ Results: ..” Five species of nematods (Epitobrilus medius, Brevitobrilus stephanskii, Raritobrilus steineri, Tobrilus gracilis, Mononchus truncates) were common at all  studied sites.”- common? Which ecological index (the commonness index?) was used to assess the commonness in species abundance? In Material and Methods, the authors did not mention such information.

9.      Figure 3 “b” should be explained in the figure caption

10.  Supplementary material- table 1- the names of species should be written in italics

Author Response

Author thank the Reviewer for useful comments and provide below our responses. Text of manuscript was corrected accordingly.

Reviewer

1.Title should start with the capital letter, please also check the font in the title “LINKS” The title is incorrectly constructed, in the Cladophora blooms instead of “during.”

Authors: Title was improved

2. I regret the lack of hypotheses, I would suggest formulating the aims of the study into the form of one or two hypotheses, but from the results obtained ( and methodology used),

Authors: The aim was clarified. Prepositions and expected results were added.

Reviewer: I can only see the comparison between the results from one month of sampling.The study aimed to determine present ecological conditions in the Neva estuary coastline: the macroalgae biomass, their contribution to the autochthonous benthic food web, and the possible influence of Cladophora blooms on composition and abundances of  macro- and meiobenthic grazers and their trophic relations.”

Authors: we added that study was conducted during the bloom (it occurs in the middle of summer).

Reviewer: Authors wrote in study aims ".. ecological conditions.." but having the results from only one sample in July 2021 they only have results from one month, one point of time. The ecological conditions change in time and space, and therefore the ecological context of the study requires repetitive sampling.

Authors: Yes, the dynamics in this study was not carried out, but we conducted studies during the succession of macroalgae in previous works (Gubelit Berezina 2010, Berezina 2005, 2008, etc.), which we took as a basis for planning this work. This study is mainly about trophic relationships, as indicated in the title of the article.

4. Methods: What kind of macroinvertebrate samples was it- is not clear from the text, were they quantitative samples?

Authors: We improved description of sampling. Yes it is quantitative. Other samplers as a benthic grab does not work at stony-sand littoral. If we will used usual botanical frame , all animals will avoid during the sampling.

Other groups of organisms were sampled in the context of area unit, but how about macroinvertebrates, the second question is if such results were comparable. This part of the text needs to be supplemented.

Authors: we added the additional table with biomass of animals in Supplement.

5. Methods: The samples were taken only in July 2021, unfortunately, I think that this is not enough to make significant and reliable results regarding the assessment of the situation, such studies should be repeated at least 3 times; otherwise, we only have basic preliminary results from one sampling. This is, in my opinion, not enough to be public in a scientific journal, and I have no conviction that they should be published. There are two options for authors, first- repeat their sampling and get more results, check if they are comparable and repeatable, or second change the title and highlight that study is a preliminary, a case study.

Authors: This work is not first step, but one-year new results of monitoring studies with started in 2003 and was already published. Every year we survived all ten places. Of course, we repeated this study more than tree times. We re-wrote more clearly our purposes in this study and revised all parts of manuscript. also all samples were repeated three times.

6. Table 1  the salinity unit should be included in the table we added.- Done
7. 2.4 Statistics: “…. Mean value…” mean from which values if the sampling was done only in one month? ---Tree times at each site.
8. 3.2. Benthic community/ Results: ..” Five species of nematods (Epitobrilus medius, Brevitobrilus stephanskii, Raritobrilus steineri, Tobrilus gracilis, Mononchus truncates) were common at all  studied sites.”- common? Which ecological index (the commonness index?) was used to assess the commonness in species abundance? In Material and Methods, the authors did not mention such information. ---We met these species at all sites. 

9. Figure 3 “b” should be explained in the figure caption --we explained it (b).

10. Supplementary material- table 1- the names of species should be written in italics –improved too.

Round 2

Reviewer 2 Report

I appreciate the response and answers of the authors to my comments. The reviewed version of the manuscript is much better than original. However, some revisions should be reviewed.

Figure 1 is not complete. please to verify. 

Table 1. Salinity is g/L or mg/L  (Line 242). ?

Figure 5 is not mentioned in the manuscript.

Line 351. P total >50 mkg/l . It is correct?

Author Response

Authors cordially thank reviewer for proposed corrections. Map was inmproved by adding geographical names of points, countries. Table 1. Salinity is g/L, it is right. Figure 5 was mentioned in the revised version of manuscript. In Line 351 P total >50 mkg/l is correct, but we changes unit in Table 1 where it was done in mg/l which is nort correct.

Reviewer 3 Report

The authors of the manuscript made an appropriate correction to the text and clarified all the reviewer questions. In this way, I consider that the manuscript could be accepted for publication and would be an interesting theme for the Diversity readership.

Author Response

Authors thank reviewer for valuable comments. English was checked agan in the revised version.

Reviewer 4 Report

After the second round of revision of the manuscript, I have no more questions. Authors correct their manuscript adequately to all suggestions included in the review.

Author Response

Thank you for your work and valuable comments.