Phytoplankton and Zooplankton Assemblages Driven by Environmental Factors Along Trophic Gradients in Thai Lentic Ecosystems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents a comprehensive study of phytoplankton and zooplankton abundance and diversity along a trophic gradient in 50 lentic water bodies in Thailand. The study uses 264 sampling points across 50 sites, providing robust spatial coverage. The results fill a significant knowledge gap in the region.

The manuscript is generally well organised and has a logical flow from introduction to conclusion. The manuscript contains valuable data and findings. However, it requires general linguistic editing by a native English speaker. In addition, several issues need to be addressed to improve clarity and editorial quality.

Specific remarks:

1. Abstract:

- Line 20: instead of "Dinophyta was more prevalent..” use the plural form "were", instead of “prevalent” use “common” or “abundant”

- Lines 27-28: Add the specific statistics and the value of the statistical correlation.

2. Introduction:

- Lines 37-38: The sentence "Lentic water bodies boast enormous contribution on biodiversity conservation..." should be rephrased for clarity and conciseness, for example “Lentic water bodies make an enormous contribution to the conservation of biodiversity, to ecosystem services and to the livelihoods of human communities”.

- Lines 40-41: Missing punctuation. Add period after at the end of the sentence.

- Line 42: "combined" is vague; specify the nature of the stressors.

- Line 67: “hyperpredate” is an unusual usage. Consider “feed on” or “actively graze on”

- Lines 53-54: I suggest adding more references:

Ochocka, A., & Pasztaleniec, A. (2016). Sensitivity of plankton indices to lake trophic conditions. Environmental Monitoring and Assessment, 188(11), 622.

Stamou, G.; Katsiapi, M.; Moustaka-Gouni, M.; Michaloudi, E. Trophic state assessment based on zooplankton communities in Mediterranean lakes. Hydrobiologia 2019, 844, 83–103. 

- Line 74-75: “existing evidence suggests that eutrophication is a growing concern in various regions” – add a reference.

2. Materials and Methods

- Line 104: Figure 1 Map should be improved (the quality is poor), the legend and scale should be more legible.

- Line 113: “Conducted in situ water quality parameters…” use “In situ measured parameters included....”

- Line 116: instead of “multi-parameter analyser” use “multi-parameter probe”

- Line 136: There’s a formula error in TSI calculation.

Currently: “TSI = (TSI (chl -a) + (TSI(TN) + TSI(TN) /2))/2” – TN is used twice.

Correct to: TSI = (TSI (chl-a) + TSI(TN) + TSI(TP))/3

As a reference for the Trophic State Index, the authors indicate Paulic et al. (14). This position is not listed in references. I suggest to calculate TSI according to the original publication - Carlson, R.E. A trophic state index for lakes. Limnol. Oceanogr. 1977, 22, 361–369

3. Results

- Copepods are repeatedly described as a "phylum," which is taxonomically inaccurate - they belong to the subclass Copepoda of the phylum Arthropoda.

- Line 165: The phytoplankton and zooplankton densities should include units for clarity: “22,653 ± 24,358 units/liter” and “5,432 ± 6,250 individuals/liter” — I suggest to use “ind. L^-1”

- Lines 187, 189: Instead of “Cladorecan” should be “Cladoceran”

- Lines 192, 194: Instead of “Cladoreran” should be “Cladoceran”

Figures:

- The legends in Figures 2 and 3 are too dense and difficult to read. I suggest adding oligotrophy, mesotrophy, etc. instead of the letters A,B,C,D.

- Figure 4 (Line 224): The figure shows trends well, but the axes need appropriate labels (e.g. 'Shannon index', 'species richness', etc.). The meaning of the letter "a” should also be explained in the caption.

- Figures 5,6,7 - Improve the visual clarity of PCA and MDS figures - the names of species and physicochemical parameters overlap and are illegible.

Table:

- Table 1 (line 238): There are alignment problems that make interpretation difficult. The phytoplankton and zooplankton lines should be clearly separated. Also note that the asterisks in the caption are incorrectly defined ("** Significantly different p > 0.01" should be "p < 0.01").

- Consider including supplementary material with full taxonomic lists and their abundances, and a table with ranges of physicochemical parameters of the water bodies tested.

4. Discussion

- Line 307: "sphere giant otolith assemblages" - This seems to be a nonsensical phrase. Please clarify or remove.

5. References

- Slightly inconsistent order of references (e.g. some citation numbers in the text do not match the actual order).

Overall, the manuscript provides a valuable and novel contribution on plankton communities across trophic gradients in the lentic water bodies of Thailand. With careful editing for grammar, terminology and figure quality, the manuscript should be of general interest to readers of Diversity. The results presented can contribute to the development of water quality indicators for lentic ecosystems in Thailand. The results have implications for freshwater biodiversity monitoring, water quality assessment and environmental management.

Comments on the Quality of English Language

English language needs improvement. The manuscript should be sent to a proofreading service.

Author Response

Please see the attachment.

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors
After reading your manuscript, I would give you some advice and comments that I believe could improve your work.

Your manuscript tackles an important and under–studied problem, how phytoplankton and zooplankton communities reflect environmental gradients across Thailand’s lentic ecosystems, and offers genuinely novel, large-scale dataset. However, to sharpen its impact and clarity you will need to substantially raise the level of scientific writing and data presentation throughout. In particular, the Methods must include precise instrument details (model and accuracy), and the TSI formula corrected to the standard form. The Results, while rich, are currently overburdened by exhaustive recitation of every percentage; instead you should distill the overarching patterns, support them with clear statistical tests (e.g., ANOVA F-values and p-values, post-hoc comparisons), and enhance your figures with annotated error bars and bolding of significant values. The Discussion needs to move beyond repeating the numbers to articulate the ecological mechanisms, why Cyanophyta dominate in nutrient-rich systems, how buoyancy or N-fixation drive responses, and to explicitly acknowledge limitations (single-season sampling, absent other chemical-parameters description) and propose something for the future. In your Conclusions, refrain from a point-by-point summary of findings; instead, frame a concise, high-level statement about how your plankton-based bioindicator framework can be adopted by water managers in tropical regions, emphasizing your contribution to global freshwater monitoring. With more substantial language precision, robust statistical justification for every claim, and an explicit description of how your regional insights extend to an international readership, your manuscript could be introduced in the literature on this important topic.

 

Comments on the Quality of English Language

The manuscript’s English is generally understandable but marred by frequent grammatical slips, awkward phrasing and inconsistent verb tenses. A thorough, line-by-line professional proofreading (or use of a scientific editing service) will be needed to ensure clarity, consistency and the polished tone expected in a publishable manuscript.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript has been greatly improved. I would like to point out a few minor remarks that need improvement.

• Line 111: The quality of the map has been improved. However, I suggest that the map should be larger.
• Figure 1: The legend is missing.
• Figure 6: The names of the parameters and plankton groups overlap.
• Figure 7: Same note as above.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Overall, the second revision has addressed many of the earlier concerns but still requires deeper contextualization and clearer visual presentation to reach its full potential. The PCA plots would be much more informative if each axis were labelled with the percentage of variance explained. In the Discussion, when you describe the dominance of Peridinium in mesotrophic waters or the persistence of copepods under eutrophic conditions, please anchor these observations in the existing Thai or worldwide literature, citing similar reservoir studies or comparable systems in terms of latitude, temperature, zone, etc. to clarify whether your patterns are broadly generalizable. Likewise, your interpretation of the MDS and PCA clusters should move beyond broad suggestions of “similar environmental conditions” and instead specify which variables (for example, high total phosphorus from upstream rice paddies or urban wastewater discharge) co‑vary with particular site groupings, ideally supported by local reports or studies. The pie charts in Figures 2 and 3 remain difficult to read. Finally, please enhance Figure 4 by adding a footnote that explains the standard error bars and the meaning of different letter groupings (e.g., “Error bars represent standard errors; different letters indicate significant differences via Tukey’s HSD at p < 0.05”), and change the generic “Biodiversity” label to “Shannon Index (Hʹ)” so that the index is unambiguously identified into the figure.

Author Response

Please see the attachment.

Author Response File: Author Response.docx