Environmental Heterogeneity of Conservation Units in the Amazon Ensures High Contribution to Phytoplankton Beta Diversity in Streams

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review for the paper "Environmental heterogeneity of conservation units in the Amazon ensures high contribution to phytoplankton beta diversity in streams" by Idelina Gomes da Silva, Ellen Guimarães Amaral Trindade, Leandra Palheta and Bárbara Dunck submitted to "Phycology".

 

Freshwater ecosystems provide a diverse array of ecosystem services that are significantly affected by various forms of land use changes, morphological alterations, and overexploitation of resources, all of which have a detrimental impact on their ecological integrity. Presently, such issues are evident in numerous stream ecosystems, with climatic changes representing the principal challenge hindering the maintenance of a favorable environmental state. The intricate nature of environmental conditions in streams is widely acknowledged and contributes to the presence of rich plankton assemblages. While ecological niches regulate the patterns observed among plankton populations, the assessment of their influence on phytoplankton diversity remains an unresolved matter. This paper presents an analysis of the beta diversity of phytoplankton in streams located in the Amazon region. The authors demonstrate that phytoplankton diversity is closely related to environmental conditions, and attribute the overall high diversity to the composition of phytoplankton assemblages. The research is well-executed, and the data are accurately analyzed employing appropriate statistical methods. Given the scarcity of data in this field, the research is compelling and offers novel insights. I have only minor suggestions for improving the manuscript.

 

Specific remarks:

 

 Abstract: I would appreciate a more detailed discussion of the core results of the study, with greater emphasis on the factors shaping phytoplankton communities in the streams.

 

 Lines 115-116: The authors indicate that five variables were recorded; however, they only specify four: pH, temperature, conductivity, and dissolved oxygen concentrations. Please correct this discrepancy.

 

 Figure 1: The font is not clearly visible in many instances. Please address this issue for improved readability.

 

 Lines 292-294 onward: The Latin names of species and genera must be italicized. Please make the necessary corrections.

 

 Figure 6: The Latin names of species and genera must also be italicized.

 

 Table S2: This table must be cited appropriately within the text.

 

 Table S2: It is essential that the Latin names of species and genera in this table are italicized.

 

 Discussion: I suggest incorporating a comparison of the main findings with other similar ecosystems and regions to enhance the context and relevance of the study.

Author Response

Comments and Suggestions for Authors

Review for the paper "Environmental heterogeneity of conservation units in the Amazon ensures high contribution to phytoplankton beta diversity in streams" by Idelina Gomes da Silva, Ellen Guimarães Amaral Trindade, Leandra Palheta and Bárbara Dunck submitted to "Phycology".

Freshwater ecosystems provide a diverse array of ecosystem services that are significantly affected by various forms of land use changes, morphological alterations, and overexploitation of resources, all of which have a detrimental impact on their ecological integrity. Presently, such issues are evident in numerous stream ecosystems, with climatic changes representing the principal challenge hindering the maintenance of a favorable environmental state. The intricate nature of environmental conditions in streams is widely acknowledged and contributes to the presence of rich plankton assemblages. While ecological niches regulate the patterns observed among plankton populations, the assessment of their influence on phytoplankton diversity remains an unresolved matter. This paper presents an analysis of the beta diversity of phytoplankton in streams located in the Amazon region. The authors demonstrate that phytoplankton diversity is closely related to environmental conditions, and attribute the overall high diversity to the composition of phytoplankton assemblages. The research is well-executed, and the data are accurately analyzed employing appropriate statistical methods. Given the scarcity of data in this field, the research is compelling and offers novel insights. I have only minor suggestions for improving the manuscript.

 

Specific remarks:

Abstract: I would appreciate a more detailed discussion of the core results of the study, with greater emphasis on the factors shaping phytoplankton communities in the streams.

Authors:  Thank you for your comment. We have added more information about our results and a more detailed discussion of the factors that influenced stream communities. Lines 21–26 and 30–32; p. 1.

Lines 115-116: The authors indicate that five variables were recorded; however, they only specify four: pH, temperature, conductivity, and dissolved oxygen concentrations. Please correct this discrepancy.

Authors: Thank you for your observation. Yes, 4 variables were measured, not 5. The sentence has been corrected.

Figure 1: The font is not clearly visible in many instances. Please address this issue for improved readability.

Authors: Thanks for the observation. We have increased the font on the map to make it more readable.

Lines 292-294 onward: The Latin names of species and genera must be italicized. Please make the necessary corrections.

Authors: Thank you for your comment. We reviewed the entire manuscript to ensure that all genera and species were italicized.

Figure 6: The Latin names of species and genera must also be italicized.

Authors: Thank you for your observation. We have changed the figure to make the Latin names of species and genera also written in italics.

Table S2: This table must be cited appropriately within the text.

Authors: Thank you for the comment. Table S2 was duly mentioned in the text (Line 271).

Table S2: It is essential that the Latin names of species and genera in this table are italicized.

Authors: Thanks for the feedback. There was indeed an error in the file that caused the species to not be italicized. We have fixed this issue and now all species are in italics.

Discussion: I suggest incorporating a comparison of the main findings with other similar ecosystems and regions to enhance the context and relevance of the study.

Authors: Thank you for your comment. We compared the main findings with other similar ecosystems and regions whenever possible (lines 378–381; 406–407), but studies with phytoplankton in streams are still in their infancy.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Please refer to the annotated PDF with calls, notes and recommendations for you. Please go over them carefully.

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GENERAL COMMENTS

The manuscript focuses on the beta-diversity patterns of micro-phytoplanktonic communities in lotic waterbodies located within and around extractive conservation units of the Brazilian Amazon. The topic is interesting, and it has not been thoroughly covered to this day.

In general, the manuscript is well structured, backed up by a sound sampling design and analytical methods. I believe it has merit and deserves publication, after undergoing minor changes.

What follows are detailed, section-by-section comments.

ABSTRACT: it provides a fair summary of the manuscript.

KEYWORDS: see my comment regarding habitat/environmental integrity.

INTRODUCTION

This section is well structured. The authors make a clear statement of how this work is novel or significant to the field. The writing style is fluent, with a good enchainment of ideas and a clear statement of objectives and hypotheses.

MATERIALS AND METHODS

The start of this section would benefit from further description of the study sites: why were these streams selected against others? What makes them representative?

I made a conceptual remark on the difference between estimated biovolume (in plankton) and biomass. Please observe this.

Other methodologies and statistical analyses are OK.

RESULTS

This section provides abundant information stemming from the sampling and the ulterior analysis. Please refer to my comments in the annotated PDF.

I would be more than surprised if the average width of the streams considered was 1.7 cm (!) as it is mentioned in line 213. This needs to be clarified, and if it holds true, then the use of term “stream” should be re-evaluated for the whole paper.

Also be careful in the use of the term “biomass”; there is a distinction (methodological and conceptual) between biomass and biovolume (which is, I believe, the parameter that you really estimated and used in your computing of HII, LCBD and SCBD. This needs to be addressed.

DISCUSSION

This section is quite good. The authors manage to integrate the results of microbial composition and abundance (biovolume) with other environmental parameters, in the context of environmental issues taking place in the study area (such as reduction in canopy cover and shading; or the alteration of riparian vegetation, increased runoff and siltation in streams).

The whole section is well supported by numerous literature references.

Please see and address my comment in lines 447-48.

CONCLUSIONS

Provides good closing to the manuscript.

FIGURES: Figures and captions OK; I made a few comments and queries. I would be illustrative to include a single, representative picture (and maybe an accompanying sketch) of a representative stream. In general, the resolution of the map in figure 1 in the proof PDF is below average, which makes it difficult to make out the details; I understand this has nothing to do with the author’s submission, but it is unfortunate nonetheless.

Comments for author File: Comments.pdf

Author Response

GENERAL COMMENTS

The manuscript focuses on the beta-diversity patterns of micro-phytoplanktonic communities in lotic waterbodies located within and around extractive conservation units of the Brazilian Amazon. The topic is interesting, and it has not been thoroughly covered to this day.

In general, the manuscript is well structured, backed up by a sound sampling design and analytical methods. I believe it has merit and deserves publication, after undergoing minor changes.

What follows are detailed, section-by-section comments.

ABSTRACT: it provides a fair summary of the manuscript.

KEYWORDS: see my comment regarding habitat/environmental integrity.

Authors: Thank you for the comment. We have corrected the keywords to “habitat integrity”.

INTRODUCTION

This section is well structured. The authors make a clear statement of how this work is novel or significant to the field. The writing style is fluent, with a good enchainment of ideas and a clear statement of objectives and hypotheses.

MATERIALS AND METHODS

The start of this section would benefit from further description of the study sites: why were these streams selected against others? What makes them representative?

Authors: Thank you for your comment. These streams were chosen because of their spatial separation to avoid spatial autocorrelation and their geomorphological characteristics characterize them as streams of 1 to 3 order.

I made a conceptual remark on the difference between estimated biovolume (in plankton) and biomass. Please observe this.

Authors: Thank you for your comment. We calculated biovolume using the appropriate measurements for each algae. We revised the manuscript to use the term biovolume.

Other methodologies and statistical analyses are OK.

RESULTS

This section provides abundant information stemming from the sampling and the ulterior analysis. Please refer to my comments in the annotated PDF.

I would be more than surprised if the average width of the streams considered was 1.7 cm (!) as it is mentioned in line 213. This needs to be clarified, and if it holds true, then the use of term “stream” should be re-evaluated for the whole paper.

Authors: Thank you for your comment. You are correct, the correct unit of measurement for channel width is meters (m). We have corrected it in the text.

Also be careful in the use of the term “biomass”; there is a distinction (methodological and conceptual) between biomass and biovolume (which is, I believe, the parameter that you really estimated and used in your computing of HII, LCBD and SCBD. This needs to be addressed.

Authors: Thank you for your comment. We calculated biovolume using the appropriate measurements for each algae. We revised the manuscript to use the term biovolume.

DISCUSSION

This section is quite good. The authors manage to integrate the results of microbial composition and abundance (biovolume) with other environmental parameters, in the context of environmental issues taking place in the study area (such as reduction in canopy cover and shading; or the alteration of riparian vegetation, increased runoff and siltation in streams).

The whole section is well supported by numerous literature references.

Please see and address my comment in lines 447-48.

Authors: Thank you for your comment. In this context of sediment ingress, the flow of water in the river is affected in a generalized way. The flow of water is reduced because areas of backwater with lower water speed are formed. Even narrowing the channel, as the sediments also remain lodged at the bottom of the river, this causes a reduction in the water current throughout the channel in that location.

 CONCLUSIONS

Provides good closing to the manuscript.

FIGURES: Figures and captions OK; I made a few comments and queries. I would be illustrative to include a single, representative picture (and maybe an accompanying sketch) of a representative stream. In general, the resolution of the map in figure 1 in the proof PDF is below average, which makes it difficult to make out the details; I understand this has nothing to do with the author’s submission, but it is unfortunate nonetheless.

Authors: Thank you for your comment. You are correct, the map was of poor image quality. We have enlarged the letters and improved the quality.

Reviewer 3 Report

Comments and Suggestions for Authors

Please refer to the attached review draft.

Comments for author File: Comments.docx

Author Response

The author investigated the beta diversity of plankton in the streams within the Amazon River Protected Area and discovered that the high environmental integrity was not directly proportional to the diversity of phytopplankton, which was an interesting phenomenon. Furthermore, the relationship between several environmental factors and the diversity of phytoplankton was analyzed, as well as the contribution of local species to the beta diversity. However, the manuscript still has many problems that need to be resolved before it can be published.

L55 MacArthur & MacArthur? Please check the author of ref-17.

Authors: Thank you for the observation. The reference has been checked and corrected. L63.

L84 When SCBD first appeared, it should have been spelled out completely.

Authors: Thank you for the comment. Now, we explain the SCBD in the paragraph introduced earlier. L85-86.

L79-86: In hypotheses 2 and 5, it seems that streams with higher HII contains more unique species and a higher species richness,, which means the same thing.

Authors: Thank you for your comment. In hypothesis 2, we want to know whether HII alters the species composition and how these species are distributed according to this index. In hypothesis 5, we would like to know whether HII influences the absolute values ​​of richness and biovolume. They are distinct hypothesis.

L114-116 5 limnological variables? pH, temperature, conductivity, DO and what?

Authors: Thank you for your comment. We made a mistake when we said 5 variables, when in fact there are 4 variables. We have corrected this in the manuscript.

L212 the streams narrow only with an average length of 1.7 cm? or m?

Authors: Thank you for your comment. You are correct, the correct unit of measurement for channel width is meters (m). We have corrected it in the text.

L215-216 The unit of temperature should be °C, and max temperature should be 30 ℃.

Authors: Thank you for your comment. You are correct. The maximum temperature is 30ºC. We have corrected it in the manuscript.

L218 O₂ should be subscripted.

Authors: Thank you for your comment. You are correct. Chemical symbols should be followed by subscript numbers. We have corrected this in the manuscript.

L232-233 In figure 3, the temperature in the CZ group was significantly higher than that in the other groups, while outside contained only one extremely high value.

Authors: Thank you for the comment. Temperatures in CZ were higher on average. We have corrected this in the manuscript. L253-254.

L287 There were not label a, b, c in the sub-figures of the picture.

Authors: Thank you for your comment. The captions are in the figures. We have redone the figures to make the letters more visible.

L373-374 The species Trachelomonas hispida should be italic.

Authors: Thank you for your comment. We reviewed the entire manuscript to ensure that all genera and species were italicized.