Eutrophication Conditions in Two High Mountain Lakes: The Influence of Climate Conditions and Environmental Pollution

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I would like to have information in changes of species spectrum (or dominants) of phytoplankton. If water bloom occurred in Lake El So, this information is important.

Author Response

REVIEWER 1

I would like to have information in changes of species spectrum (or dominants) of phytoplankton. If water bloom occurred in Lake El So, this information is important.

RESPONSE. Thank you very much for the comments.

In this study, we did not show the dominants species in the lakes, we would have liked to carry out this study. However, this work was focused on evaluation of eutrophication by index. However, in another previous publication of our group, we exhibited some species as indicators of eutrophication (https://doi.org/10.1080/02757540.2024.2425287).

Reviewer 2 Report

Comments and Suggestions for Authors

Overall this is a significant work but needs significant improvements before it can be considered for publication in Hydrology, MDPI.

1.     please revise the Abstract, Introduction, and Conclusion for better clarity and focus? The Abstract especially should clearly outline the problem, your method, the main finding, novelty, and its broader impact.

2.     In the introduction (line-36) please include cite additional recent articles on climate change, hydroclimatic extremes (doi.org/10.1016/j.jenvman.2024.121375), eutrophication and ecosystem health (doi.org/10.1016/j.scitotenv.2024.175523) which will strengthen the statement

3.     The methodology section describes sampling from different lake points across various seasons. However, it lacks detailed information on how these sites and timing were chosen and whether they adequately represent overall lake conditions.

4.     The paper identifies agrochemicals as the principal pollutants but does not thoroughly explore all potential nutrient sources impacting the lakes. A more comprehensive investigation into other sources such as atmospheric deposition, local wildlife, and direct human activities (doi.org/10.1007/978-981-97-7474-6_42) within the watershed would provide a fuller picture of the nutrient dynamics.

5.     Please update your literature review with more recent studies from the last 3-4 years to underscore the current relevance and broader impact of your findings.

6.     For your study on eutrophication in high mountain lakes, it would be beneficial to provide additional details on your sampling choices, such as the rationale for selecting specific lakes and sampling points. Expanding on the statistical methods used to analyze climatic and water quality data could also help support the validity of your conclusions.

7.     While the study briefly discusses the impact of climatic variables on eutrophication, a deeper analysis of long-term climate trends and their interactions with lake dynamics is missing. Given the unique high-altitude environment of the lakes, incorporating historical climate data and examining long-term trends would significantly contribute to understanding how climate change might be influencing these ecosystems.

8.     Please ensure that the fonts in your figures are consistent. Additionally, enhance the captions for figures and tables to provide clearer and more detailed explanations of what is depicted and how it relates to your study's findings.

9.     Please make the objectives and overarching aim of your study more explicit to help readers clearly understand the research goals and specific contributions of your work. Additionally, enhance the introduction by clarifying how this work is novel.

10.  Please align the study goals with the discussion more closely, detailing how your findings compare with or differ from prior research and their implications for ecological management.

11.  Discuss the effects of using different rainfall datasets and model calibration on your results. Consider citing relevant studies on nitrogen dynamics (doi.org/10.3390/nitrogen5040065) and hydrological models (doi.org/10.1016/j.ejrh.2024.102134) to enhance your methodological framework.

Comments on the Quality of English Language

The manuscript presents valuable research on the eutrophication of high mountain lakes under the influence of climatic conditions and environmental pollution. However, the quality of the English language requires significant improvement to meet the publication standards of an international journal. Several instances of awkward phrasing, grammatical errors, and occasional unclear expressions detract from the overall clarity and professionalism of the text. For example, phrases like "Lakes have experimented changes" should be revised to "Lakes have undergone changes" to correct the language and enhance precision. I recommend a thorough revision of the manuscript by a native English speaker or a professional editing service to address these issues. 

Author Response

REVIEWER 2

1. please revise the Abstract, Introduction, and Conclusion for better clarity and focus? The Abstract especially should clearly outline the problem, your method, the main finding, novelty, and its broader impact.

RESPONSE. Thank you very much for the comments.

The abstract, Introduction, and Conclusion contains the focus of the study or problem, which corresponds to eutrophication of Lakes El Sol and La Luna. The focus and principal finding are available in abstract, lines15-22; introduction, lines 94-100. Conclusions, lines 416-450.

The novelty of the study was indicated as the evaluation of eutrophication in high mountain lakes in Mexico, which are only in the country, and they are environmentally important, which it is indicated in various lines of manuscript. 

2. In the introduction (line-36) please include cite additional recent articles on climate change, hydroclimatic extremes (doi.org/10.1016/j.jenvman.2024.121375), eutrophication and ecosystem health (doi.org/10.1016/j.scitotenv.2024.175523) which will strengthen the statement.

RESPONSE. Thank you very much for the comments.

We included the suggested references in lines 37 and 45.

3. The methodology section describes sampling from different lake points across various seasons. However, it lacks detailed information on how these sites and timing were chosen and whether they adequately represent overall lake conditions.

RESPONSE. Thank you very much for the comments.

In attendance of the observation, we added lines 147-157 to explain the selection of sampling sites. 

4. The paper identifies agrochemicals as the principal pollutants but does not thoroughly explore all potential nutrient sources impacting the lakes. A more comprehensive investigation into other sources such as atmospheric deposition, local wildlife, and direct human activities (doi.org/10.1007/978-981-97-7474-6_42) within the watershed would provide a fuller picture of the nutrient dynamics.

RESPONSE. Thank you very much for the comments.

The objective of the research was to determine the eutrophication status of the lakes El Sol and La Luna. We did not analyze in detail the dynamics of nutrient contamination from different sources. However, this topic is also very interesting for another stage.

The suggested article was read and placed in the introduction reference [5], indicating the importance of this type of study in water bodies.

5. Please update your literature review with more recent studies from the last 3-4 years to underscore the current relevance and broader impact of your findings.

RESPONSE. Thank you very much for the comments.

Our study is focused on high mountain lakes and most of the citations are recent because eutrophication studies on high mountains are few. Other references from last year were included because they have information that helps to compare and discuss. In the new version of manuscript were introduced references 2, 4, 5, 8, 

6. For your study on eutrophication in high mountain lakes, it would be beneficial to provide additional details on your sampling choices, such as the rationale for selecting specific lakes and sampling points. Expanding on the statistical methods used to analyze climatic and water quality data could also help support the validity of your conclusions.

RESPONSE. Thank you very much for the comments

In attendance of the observation, we added lines 147-157 to explain the selection of sampling sites. 

Also, a statistical analysis was shown to support the conclusions, and we would have liked to show data on a more detailed statistical analysis; however, for expanding the analysis we require more data than we are now collecting for another manuscript.

7. While the study briefly discusses the impact of climatic variables on eutrophication, a deeper analysis of long-term climate trends and their interactions with lake dynamics is missing. Given the unique high-altitude environment of the lakes, incorporating historical climate data and examining long-term trends would significantly contribute to understanding how climate change might be influencing these ecosystems.

RESPONSE. Thank you very much for the comments

There is much reason in your comments, and we also agree. We are now continuing with the work to expand the study and have more data to understand and show the reason for the eutrophication of the lakes; however, this first study is only an analysis to determine the status of the eutrophication of the lakes.

8. Please ensure that the fonts in your figures are consistent. Additionally, enhance the captions for figures and tables to provide clearer and more detailed explanations of what is depicted and how it relates to your study's findings.

RESPONSE. Thank you very much for the comments

We review and correct titles of figures and tables.

9. Please make the objectives and overarching aim of your study more explicit to help readers clearly understand the research goals and specific contributions of your work. Additionally, enhance the introduction by clarifying how this work is novel.

RESPONSE. Thank you very much for the comments

The abstract, Introduction, and Conclusion contains the focus of the study or problem, which corresponds to eutrophication of Lakes El Sol and La Luna. The focus and principal finding are available in abstract, lines15-22; introduction, lines 94-100. Conclusions, lines 416-450.

The novelty of the study was indicated as the evaluation of eutrophication in high mountain lakes in Mexico, which are only in the country, and they are environmentally important. In addition, the manuscript contains the first study of pollution and eutrophication of the lakes, which is indicated in various lines of manuscript.

 

10. Please align the study goals with the discussion more closely, detailing how your findings compare with or differ from prior research and their implications for ecological management.

RESPONSE. Thank you very much for the comments

We indicated in the manuscript that this contains the first study of lake pollution and eutrophication. There are other studies, where some isolated parameters of the lakes are presented, and we discuss the differences between the data from other previous studies to explain the changes found in this work.

11. Discuss the effects of using different rainfall datasets and model calibration on your results. Consider citing relevant studies on nitrogen dynamics (doi.org/10.3390/nitrogen5040065) and hydrological models (doi.org/10.1016/j.ejrh.2024.102134) to enhance your methodological framework.

RESPONSE. Thank you very much for the comments

The mentioned works are interesting and could be included in future studies; however, the present study of the lakes does not include nitrogen dynamics, nor hydrological models.

 

Reviewer 3 Report

Comments and Suggestions for Authors

This article is intending to find out the correlation between eutrophication (nutrient over-enrichment within two aquatic ecosystems-lakes) and climatic warming. The Growing anthropogenic and natural disruptions are posing serious challenges to the sustainability of aquatic ecosystems worldwide and this affects both economic and health state of surrounding communities, and not only.

 

 

# Paragraph 2 of the Introduction (lines 42-44) need to be supported by references.

 

# In between lines 102-105, authors state “The lake basin is characterized by andesitic-dacitic boulders, sparse vegetation (alpine meadow) and alpine grassland type, composed of some species of mosses, 106 grasses, lichens and a cold climate”. Please be more specific on vegetation type and species, and then readers can better understand not only importance of lakes, but biodiversity as well and that might be inspiring for further resilience measures.

 

# Figure 1 needs orientation (N).

 

# Under 2.4 Analysis of water quality and eutrophication parameters, do you measure SD (m)?

 

# Again under this sub-section, list the methods/Standard ones used for measuring Cha, TP and TN.

 

# Seems that this is the only study dedicated to these two lakes, do you believe that eutrophication has been happen recently and was not the case of a decade or two ago?

 

#Please before assessing TSI, convert values to µg/L, and after that calculate it.

 

I this article need further deep reconsiderations before being accepted for publications.

Author Response

REVIEWER 3

This article is intending to find out the correlation between eutrophication (nutrient over-enrichment within two aquatic ecosystems-lakes) and climatic warming. The Growing anthropogenic and natural disruptions are posing serious challenges to the sustainability of aquatic ecosystems worldwide and this affects both economic and health state of surrounding communities, and not only.

1. Paragraph 2 of the Introduction (lines 42-44) need to be supported by references.

RESPONSE. Thank you very much for the comments

We added references 3, 4 5 supporting lines 42-45

2. in between lines 102-105, authors state “The lake basin is characterized by andesitic-dacitic boulders, sparse vegetation (alpine meadow) and alpine grassland type, composed of some species of mosses, 106 grasses, lichens and a cold climate”. Please be more specific on vegetation type and species, and then readers can better understand not only importance of lakes, but biodiversity as well and that might be inspiring for further resilience measures.

RESPONSE. Thank you very much for the comments

We specified on the vegetation type in the lakes

3. Figure 1 needs orientation (N).

RESPONSE. Thank you very much for the comments

We specified the orientation in Figure 1.

4. Under 2.4 Analysis of water quality and eutrophication parameters, do you measure SD (m)?

RESPONSE. Thank you very much for the comments

Yes, we measure SD in m, it was indicated in Table 3 and other lines of results.

5. Again under this sub-section, list the methods/Standard ones used for measuring Cha, TP and TN.

RESPONSE. Thank you very much for the comments

We have written in the section of methodology the cite of used methods Chl-a, TP and TN. Lines 179-181.

6. Seems that this is the only study dedicated to these two lakes, do you believe that eutrophication has been happen recently and was not the case of a decade or two ago?

RESPONSE. Thank you very much for the comments

Certainly, a study of eutrophication had not been carried out and there is only isolated data from past years; however, comparing this data with recent data shows that there are changes that are beginning to be alarming and to date there are already indicators of eutrophication, and that the reduction in the perimeter of the lakes is very noticeable.

7. Please before assessing TSI, convert values to µg/L, and after that calculate it.

RESPONSE. Thank you very much for the comments

The units mg/m³ are equivalent to µg/L; thus, the TSI is equal  

8. This article need further deep reconsiderations before being accepted for publications.

RESPONSE. Thank you very much for the comments

We incremented the discussion of results a review the manuscript, for considering of publication

 

Reviewer 4 Report

Comments and Suggestions for Authors

The article is worth publishing due to the importance of the topic. It presents the results of environmental monitoring of Lakes El Sol and La Luna  to evaluate the eutrophic status and the influence of water pollution and climatic factors. I have some comments to improve the presentation quality and soundness of the article further.

1- Lin2s 30-31,page 1: due to the importance of the topic.

2- Add a recommendation based on the study's results in 1-2 lines to close the abstract.

3-(a) Below line 101, provide a detailed flowchart of the methodology to enable your audience to understand your methodology without reading it in detail and to help junior researchers repeat your research on another area.

 (b) You can write as follows: Figure 1 presents the flowchart of the adopted methodology which will be explained in details in the coming subsections.

(c) Then renumber the subsequent figures and the citations.

4- Lines 153-160, page 4: Either to explain the sampling, storing and analysis in details or cite a references for the standard your followed.

5- Line179: show which software you used for the statistical analysis and cite the source, if applicable.

6- Line 187page 5, write the discussion in a separate section.

4 Discussions

In the discussions, discuss the accuracy of the analysis, significance of the results, and limitations of your research. and how this research could repeated for which places/lakes.

7- Next to line 450, page 13, add a recommendation section.

6. Recommendation: Recommendations can be for future studies, policy planners, decision-makers, and/or stakeholders.

 

 

Author Response

REVIEWER 4

The article is worth publishing due to the importance of the topic. It presents the results of environmental monitoring of Lakes El Sol and La Luna to evaluate the eutrophic status and the influence of water pollution and climatic factors. I have some comments to improve the presentation quality and soundness of the article further.

1. Lin2s 30-31, page 1: due to the importance of the topic.

RESPONSE. Thank you very much for the comments

We already made some changes to those lines.

2. Add a recommendation based on the study's results in 1-2 lines to close the abstract.

RESPONSE. Thank you very much for the comments

Lines 25-39 contains the principal results of the study

3. (a) Below line 101, provide a detailed flowchart of the methodology to enable your audience to understand your methodology without reading it in detail and to help junior researchers repeat your research on another area. (b) You can write as follows: Figure 1 presents the flowchart of the adopted methodology which will be explained in detail in the coming subsections (c) Then renumber the subsequent figures and the citations.

RESPONSE. Thank you very much for the comments

We did not introduce a flow diagram as suggested. Generally, such flow diagrams are not placed in manuscripts. In this paper the methodology comprises studies of changes in lake shape and perimeters, water characteristics of lakes, eutrophication parameters in lakes, and incidence of climatic parameters on eutrophication status and changes in lake perimeters, analyzing by Pearson correlations, which is indicated in methodology section.

4- Lines 153-160, page 4: Either to explain the sampling, storing and analysis in details or cite a references for the standard your followed.

RESPONSE. Thank you very much for the comments

In attendance of the observation, we added lines 147-157 to explain the selection of sampling sites and lines contain the cites. 

5. Line179: show which software you used for the statistical analysis and cite the source, if applicable.

RESPONSE. Thank you very much for the comments

We indicated the data statistical analysis was conducted using Origin software version 10.5. Lines 201-202.

6. Line 187 page 5, write the discussion in a separate section.

RESPONSE. Thank you very much for the comments

We do not separate the discussion section, because the results are inherent.  

7. In the discussions, discuss the accuracy of the analysis, significance of the results, and limitations of your research. and how this research could be repeated for which places/lakes.

RESPONSE. Thank you very much for the comments

The methodology for assessing eutrophication is carried out by including different variables; however, eutrophication indices indicate the status. The indices are already in the literature and can be applied to any lake.

We added the limitation of study. Lines 463-471.

8. Next to line 450, page 13, add a recommendation section.

RESPONSE. Thank you very much for the comments

We added the limitation of study and recommendation. Lines 463-471.

6. Recommendations can be for future studies, policy planners, decision-makers, and/or stakeholders.

RESPONSE. Thank you very much for the comments

We added the recommendation in Lines 463-471.

Reviewer 5 Report

Comments and Suggestions for Authors

Dear authors,

Thank you for submitting your interesting manuscript. I have just few suggestions:

1) Probably, you might modify the title to "Eutrophication conditions in two tropical alpine lakes: Influence of climate and environmental pollution"?

2) Please, consolidate the abstract and introduce the main tasks of your project.

3) In the chapter 2.1., please add there standard facts of climate and water balance (Koppen climate district, temperature and precipitation regime, potential evapotranspiration and aridity index), as well as the natural eutrophication status and prepositions to water quality.   

4) Chapters 2.2., 2.3., 2.4. and 2.5. should be integrated in one chapter introducing already your observations. 

5) In chapter 3.1., L. 195-197, the periods 2019-2020 or 2021-2023 are too short to make adequate deduction on precipitation sums at your field. 

Generally, the field study seems to be relatively short to get the climate change impact. You got a lot of valuable information, probably the necessary long-term trends in the climate (and related water balance and the lake perimeter) could be still reconstructed (for example from the nearby climate stations, satellite imagery etc.).

Author Response

REVIEWER 5

Dear authors,

Thank you for submitting your interesting manuscript. I have just few suggestions:

1) Probably, you might modify the title to "Eutrophication conditions in two tropical alpine lakes: Influence of climate and environmental pollution"?

RESPONSE. Thank you very much for the comments

We consider the proposed title to be similar to the one already contained in the manuscript; however, we did not make the suggested change because in the text of the manuscript we used high mountain lakes to describe the study sites.

2) Please, consolidate the abstract and introduce the main tasks of your project.

RESPONSE. Thank you very much for the comments

Lines 20-24 of abstract and lines 98-99 of introduction contains the tasks of the manuscript.

3) In the chapter 2.1., please add there standard facts of climate and water balance (Koppen climate district, temperature and precipitation regime, potential evapotranspiration and aridity index), as well as the natural eutrophication status and prepositions to water quality.  

RESPONSE. Thank you very much for the comments

Lines 116-118 contains the temperature of the lakes area, and climatic temperature, which coincide with Koppen; however, with the recollected data of climatic variables, we cannot do a balance of these variables.      

4) Chapters 2.2., 2.3., 2.4. and 2.5. should be integrated in one chapter introducing already your observations.

RESPONSE. Thank you very much for the comments

We do not consider the integration of sections because the division of sections allows us to see what was done in each case and the presentation of the results; in integration, this difference is lost.

5) In chapter 3.1., L. 195-197, the periods 2019-2020 or 2021-2023 are too short to make adequate deduction on precipitation sums at your field.

RESPONSE. Thank you very much for the comments

The data presented in the lines mentioned correspond to monthly and annual averages of precipitation in that period. The period is short and was taken as such, to look for coincidences with the data available on eutrophication parameters, water quality and lake perimeter.

We continue working to carry out a more in-depth study and show it later; however, in this manuscript, for the period shown, the data obtained are the result of that period.

6. Generally, the field study seems to be relatively short to get the climate change impact. You got a lot of valuable information, probably the necessary long-term trends in the climate (and related water balance and the lake perimeter) could be still reconstructed (for example from the nearby climate stations, satellite imagery etc.).

RESPONSE. Thank you very much for the comments

We agree with your assessments. Also, we are aware of the limitations of the research and that further studies are needed, which we are currently in charge of. However, this is the first study of eutrophication in the lakes and the objective was to determine the eutrophication status of the lakes and the possible causes, which is presented in this manuscript, so that the data could be considered in the formulation of strategies and the mitigation action plan.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors, thanks for improving the manuscript. Your work looks much better now, and I believe its ready to be published in Hydrology.

There is some redundancy in results & discussion sections, if possible please concise it a bit. 

Author Response

REVIEWER 2

Dear authors, thanks for improving the manuscript. Your work looks much better now, and I believe its ready to be published in Hydrology.

There is some redundancy in results & discussion sections, if possible please concise it a bit. 

RESPONSE. Thank you very much for the comments.

We have revised the entire manuscript to eliminate redundancies in the results and discussion section and removed two paragraphs in lines 341-346.

Reviewer 3 Report

Comments and Suggestions for Authors

Manuscript has been improved, I am happy with this

Author Response

REVIEWER 3

Comments and Suggestions for Authors. Manuscript has been improved, I am happy with this.

RESPONSE. Thank you very much for the comments.

We appreciate your time in reviewing the manuscript and we hope to have addressed your suggestions correctly.

Reviewer 5 Report

Comments and Suggestions for Authors

Thank you for the revision.

Author Response

REVIEWER 5

Comments and Suggestions for Authors

Thank you for the revision.

RESPONSE. Thank you very much for the comments.

We appreciate your time in reviewing the manuscript and we hope to have addressed your suggestions correctly.