Effects of Aquatic Vegetation Decomposition River Nutrient Conditions: A Case Study on the Jeonjucheon River, South Korea

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. The study's aim to evaluate the impact of decomposing river vegetation on water pollution, particularly focusing on the Jeonjucheon river section, is commendable. However, it would be beneficial to elaborate more on the selection criteria for the river section and the choice of vegetation species analyzed. Additionally, a more detailed description of the experimental setup, including control measures and replicates, would strengthen the methodology section.

2. The statistical analysis using one-way ANOVA is appropriate for the study. However, the manuscript could benefit from a deeper exploration of the results, including discussing any potential limitations or biases in the data. Also, a comparison with similar studies in other geographical locations could provide a broader context to the findings.

3. The manuscript is well-organized, but there are sections where the clarity could be improved. For example, the introduction could provide a more comprehensive background on the subject. Also, the discussion section could be more detailed in connecting the study's findings with broader environmental implications.

4. Several paper relate to the water pollution suggested to cited. (e.g. ECOL CHEM ENG S. 2014;21(1):89-99; Front. Chem. 2018, 6:464. doi: 10.3389/fchem.2018.00464)

Comments on the Quality of English Language

The English should be polished. 

Author Response

Dear Reviewer,

Thank you for allowing us to submit a revised draft of our manuscript titled “Effects of Aquatic Vegetation Decomposition River Nutrient Conditions: A Case Study on the Jeonjucheon River, South Kore” (manuscript ID: sustainability-2860560)” for publication in Sustainability.

We appreciate the effort and time you have dedicated to providing valuable feedback on our manuscript. We are grateful to the reviewers for their valuable comments on our paper. Your insightful comments have led to improvements in the current version of the manuscript. We have carefully considered your comments and have addressed them meticulously. We hope that the revised manuscript meets your high standards. We will be happy to address any further queries you may have.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

There is considerable interest in the prospects of using aquatic plants for bioremediation of nutrient pollution, and I commend the authors for working on this timely issue.  Unfortunately, the conceptualization and methodology behind this paper are not sufficiently strong to advance the state of science in this area.

Conceptualization: Aquatic plants and their associated epiphytes take up dissolved nutrients from the water column and sediments, store these in their tissues for a period of time (e.g., a seasonal cycle in temperate climates), and subsequently re-release these nutrients in dissolved (following re-mineralization) or particulate (as plant fragments) form upon senescence.  Unless the plants are harvested prior to senescence, they have no net effect on the nutrient balance of the ecosystem (i.e., on TN or TP).  However, the plants do have a transient, transformative effect on nutrient fractions as during their active growth phase they are removing dissolved nutrients and sequestering them in tissues.  In this aspect, they may provide a short-term benefit for water quality by removing dissolved nutrients that might otherwise be used to fuel algal blooms.  Thus, the role of aquatic plants in the nutrient cycle is based on their transformative effect (dissolved vs. particulate, inorganic vs. organic), not on their net effect (TN and TP).  A study to assess their effects necessarily requires an analysis of nutrient fractions, not just TN and TP.  These ideas are missing from the conceptual basis of the study (Introduction) and also from the methodology in how the experiments were carried out.

Other comments

There is much that is unclear to the reader at the outset of this paper (Title and Abstract).  For example, the term ‘water purification plants’ is likely to be mis-interpreted as engineered facilities for treating water.  Substituting ‘aquatic vegetation’ would be helpful, but ‘purification’ is also confusing in this context as it implies bioremediation (e.g., growing rafts of plants to remove nutrients by harvesting of the plants).  As this paper focuses on naturally occurring vegetation, it would be simpler to state that this is a study on the effects of decomposition of aquatic vegetation on nutrient conditions in rivers.  There are many other aspects of the results presented in the Abstract that are unclear.  For example, ‘elution loads’ are given as mg/L.  Presumably this value would be highly dependent on the amount of plant material relative to the incubation volume, and therefore not comparable across studies.  This result should be expressed as a mass of N or P released per unit of plant mass, or better, if you know the N and P content of the plant material at the start of the incubation, you could express these results as % loss.  There is a large literature on the decomposition rates of terrestrial and aquatic vegetation, which are mostly expressed per unit mass of plant material.  Other results are similarly confusing (e.g., contributions to ‘water pollution’ as %; % of what?).

There were many terms that I did not understand, and which were not explained: ‘soil sweep’, ‘sprayed nutrients such as carbon dioxide’, ‘flow path extension’, ‘river extension’, ‘national river section’, ‘vegetation inflow rate’, etc.

Methods: were the decomposition experiments conducted in the light or dark?  Were the tanks mixed?  How do you collect a representative sample of the decomposing plant slurry?  Should a repeated measures ANOVA be used to assess the statistical significance of the results?  I could not understand how you determined the proportional contributions of each species to the various sections of the river.

Results: if the plants are fragmenting during the decomposition experiment, and you are measuring Total N and P (inclusive of plant fragments), then can this be considered a measure of elution?  I thought that ‘elution’ implied that the nutrients were entering the dissolved state (i.e., as DIN or DON). 

 

Comments on the Quality of English Language

No comments.

Author Response

Dear Reviewer,

Thank you for allowing us to submit a revised draft of our manuscript titled “Effects of Aquatic Vegetation Decomposition River Nutrient Conditions: A Case Study on the Jeonjucheon River, South Kore” (manuscript ID: sustainability-2860560)” for publication in Sustainability.

We appreciate the effort and time you have dedicated to providing valuable feedback on our manuscript. We are grateful to the reviewers for their valuable comments on our paper. Your insightful comments have led to improvements in the current version of the manuscript. We have carefully considered your comments and have addressed them meticulously. We hope that the revised manuscript meets your high standards. We will be happy to address any further queries you may have.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Interesting work, relevant in areas where we see pollution in streams and rivers.

Your work can inform post-graduate studies.

Author Response

Thank you for your positive evaluation of our paper. We will reflect the opinions of other reviewers to further improve the completeness of the paper.

Reviewer 4 Report

Comments and Suggestions for Authors

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you for allowing us to submit a revised draft of our manuscript titled “Effects of Aquatic Vegetation Decomposition River Nutrient Conditions: A Case Study on the Jeonjucheon River, South Kore” (manuscript ID: sustainability-2860560)” for publication in Sustainability.

We appreciate the effort and time you have dedicated to providing valuable feedback on our manuscript. We are grateful to the reviewers for their valuable comments on our paper. Your insightful comments have led to improvements in the current version of the manuscript. We have carefully considered your comments and have addressed them meticulously. We hope that the revised manuscript meets your high standards. We will be happy to address any further queries you may have.

Author Response File: Author Response.pdf

Reviewer 5 Report

Comments and Suggestions for Authors

Abstract: it was not clear what the work was about and what made it different.

Introduction:

- Second paragraph: what types of plants are used for this purpose?

- Lines 49-53: I suggest mentioning the difference between this work and the work already done on water pollution.

Materials and Methods:

- in topic: sampling, why were these species chosen? It's not clear from the methodology

- I suggest removing figure 2. The methods used to analyze the samples would be better described.

Results:

- in topic: Dissolution Test Results, the results of the T-N and T-P analyses are fundamental to the study, so I suggest improving the way the results are presented in another graph, with a better structure. I also suggest not using a continuous line between the points.

- I suggest improving the discussion of the results in figure 6 and table 6, which are fundamental for analyzing removals.

Conclusion:

In the conclusion, I suggest not repeating the data obtained, but rather in general terms. It would be interesting if the contribution of the study, future prospects and challenges encountered were shown again.

Author Response

Dear Reviewer,

Thank you for allowing us to submit a revised draft of our manuscript titled “Effects of Aquatic Vegetation Decomposition River Nutrient Conditions: A Case Study on the Jeonjucheon River, South Kore” (manuscript ID: sustainability-2860560)” for publication in Sustainability.

We appreciate the effort and time you have dedicated to providing valuable feedback on our manuscript. We are grateful to the reviewers for their valuable comments on our paper. Your insightful comments have led to improvements in the current version of the manuscript. We have carefully considered your comments and have addressed them meticulously. We hope that the revised manuscript meets your high standards. We will be happy to address any further queries you may have.

Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have greatly improved the article