Seasonal Change in Oxidative Stress Parameters in Amphipods Gammarus lacustris in the Tributaries of Lake Sevan (Armenia) with Different Hydrophysical and Hydrochemical Characteristics

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Letter to Authors
hydrobiology-4256067-v1
Seasonal changes in oxidative stress parameters in amphipods Gammarus lacustris in the tributaries of Lake Sevan (Armenia) with different hydrophysical and hydrochemical characteristics
Hranush Melkonyan, Grigorii M Chuiko, Nadezhda Kholmogorova, Bardukh Gabrielyan, Hermine Yepremyan, Vardan Asatryan, Marine Dallakyan, Zhanna Mkrtchyan, Gayane Shahnazaryan, Hripsime Kobelyan

260421

Dear authors,
Monitoring ecosystem health is essential for management and conservation of natural resources. In this line, your research on SOS biomarkers in a gammarid species will make sense. Choose of that common species as a model is fine. It is thus worth publishing your MS in the journal, when adequately written. 
This MS is, however, wastefully long with 22(!) pages and 663(!) lines from the title to end of conclusion. You might think there is no size limitation of papers published in open journals, but readers' short term working memory when reading does have. Long tedious back and forth arguments disturb readers' understanding, or they would through your paper away. Do you like to read looooong papers in English? Your paper should be as concise as possible to make it clear, direct, strong and straightforward. Compact = impact.
In addition, the top three paragraphs seem generated by AI. Use of AI is not always bad. It is something like use of English editing service by authors from non-English-speaking countries. When used, however, you must make a declaration of AI use in a back matter.  
See below for detail. 

L21
necessitating (what do you need?) -> necessitating assessment of 

L39 keywords
oxidative stress; Gammarus lacustris; tributaries; Lake Sevan -> replace
Avoid listing words which appear also in the title. Duplicate hits upon computer search do not make sense. Give words that do not appear in the title to draw attention from wider readership. Posting words that neither appear in the abstract is better, because even in full-text search/indexing robots may not weigh much on words deeper (posterior) in the text. Hint (in an alphabetical order): amphipod, brackish-water, crustacean, ecosystem health, inflow, Ramsar wetland, redox, etc. 

L56
[11, 12] -> choose one
Too extensive self-citation is not allowed. 

L58
[13, 14] -> choose one
Your MS is not a showcase of your reading. 

L62
[14, 17] ^> choose one
Too extensive self-citation is not allowed. 

L68
(LPO) (appears only twice) -> delete

L70
(GPO) (never appear again) -> delete

L71
[18, 19, 20] -> choose one

L73
[21, 22] -> choose one

L76
[23, 24, 25] -> choose either of [24] or [25]
Citing [23] is irrelevant. 

L78
[26, 27, 28, 29] -> choose one (a review paper or most recent is preferable)
Wording like [XX and references therein] is one point. 

L83-86
Delete. Omitting one paragraph here and there, one sentence here and there, one phrase here and there, one word here and there will make your MS compact in the end. 

L87
MDA -> malondialdehyde (MDA)

L88
from (information deficient) -> from three {inflows, tributary} to the lake, 
Words in wavy braces are options. 

L103-104
Delete (redundant). Wording like "X is shown in figure/table Y" imposes killing readers' times to read such an information-deficient sentence telling only that there is a figure/table. You should present an outline or a perspective drawn from the figure/table and cite it in parentheses at the end. You may cite the table at the end of next sentence in parentheses. 

L106,139,etc (many)
studied (verbose) -> delete
Self-explanatory words can be omitted. I think you are telling STUDIED matters only. 

L111
municipal wastewater -> untreated or insufficiently treated municipal wastewater 
agricultural surface runoff -> diffused agricultural surface runoff

L112
alterations of the river channel -> alterations of the river channel (bank reinforcement and channel regulation)

L116
the Vardenis and Geghama volcanic ranges, including Mount Armaghan -> mountain ranges up to 2840 m
Presenting three unfamiliar names of places one after another exhausts readers' short term memory spaces. On the other hand, presenting the elevation will help readers' understanding of the winter snow cover. 

L119
studied (does not make sense) -> {localities, rivers, tributaries}
Words in wavy braces are options. 

L125
What is the last settlement?

L127-131
The investigated river sections .. channel regulation). (redundant) -> delete

L153-156
Move to L146 omitting "(K, Na, Ca, Mg, total Fe, Cu, Zn, Pb, and Cd)". 

L166
duplicate. Protein contents were measured using the method of Bradford (1976) with bovine serum albumin as a standard [31]. -> duplicate by the standard colorimetric assay [31]. 
Textbook matters can be simplified. 

L168
malondialdehyde (MDA) -> MDA

L168-217
Make one paragraph. 

L169
(TBARS) (appears only once later) -> delete
LPO -> lipid peroxidation products

L170-178
Trichloroacetic acid .. for calculations. -> delete
Textbook matters can be omitted. When readers are interested in its details, they may visit the citing literature. 

L180
The catalase (CAT) -> CAT
See L87. 

L184
The superoxide dismutase (SOD) -> SOD
See L88. 

L186-190
Measurement was performed .. sample aliquot. -> delete
Textbook matters can be omitted. 

L190
SOD activity determination was performed at 540 nm and -> SOD activity was 

L193-198
The reduced glutathione (GSH) .. supernatant fraction. -> delete
Textbook matters can be omitted. 

L201
(GSSG) -> delete

L201-206
The reaction mixture .. at 25ﾟC. -> delete

L210
The glutathione transferase (GST) -> GST

L211-214
The reaction .. for 3 min. -> delete

L215
measured using a molar extinction coefficient of 9.6×103 M-1 cm-1 and -> delete

L221
What is LSD?
, p=0.05 -> at a significant level of p=0.05

L233-235
The analyzed .. in Table 1. -> delete

L272
category -> category according to the national standards of Armenia (http://env.am/en/environment/environmental-monitoring, accessed 10.04.2025)
Top-heavy documents are preferable, because readers can stop reading anywhere getting the best information up to that point. 

L276
The permanganate oxygen demand (COD) -> COD

L343-345
The concentrations .. in Table 2. -> delete

L385
Argichi rivers. -> Argichi rivers (Table 3).

L386
(Table 3) -> delete

L391-393
means marked .. p = 0.05). -> superscripts indicate letter-based grouping among months of each river (alphabets ? ) and among rivers of each month (numerics ? ) by one-way ANOVA, LSD test, p = 0.05. 

L394
from the studied rivers -> delete

L398
In the Gavaraget River -> In the Gavaraget River, (insert a comma)

L401
limits -> limits,

L425 figure picture
Move Argichi to the bottom to align with the describing order in the main text. 

L429
Mahalanobis distance (MD) -> MD
See L224. 

L468 discussion
You seem yourself disturbed by your loooong document. You seem losing yourself by memory overflow. Many of the citing items limited to this section [40-63] could be replaced with those citing in the introduction section [1-29], if your document is well structured in which arguments in these two sections correspond with each other. You may thus reduce one more page omitting several references to save short-term memory spaces of readers and yourself. 

L469-478
Aquatic animals, .. of aquatic invertebrates [20]. -> delete
Duplicated introductory notes are unnecessary. 

L479-514
Delete. See L138. Do not bloat your MS with looooong excuse statements. When you like to make excuse for your negligence of sex, add one sentence to L652. 

L538,566
(http://env.am/en/environment/environmental-monitoring, accessed 10.04.2025) -> delete

L653 conclusion
Delete. 
Conclusion section is not mandatory. If you like to make this section sense, leave brief remarks (< 100 words) corresponding to the opening remarks in the introduction in L43-50. How does your research contribute to the freshwater environmental general issue?

L677
If you used AI for document generation, add a declaration here. Consult with the journal office how to do it. 

L678 references
Check the reference list carefully again from the beginning. Reference lists are frequently hotbeds of errors. You might add, omit or swap citation in the main text on the way internal revision. Numbering of the references might then shift. If so, readers think you are making irrelevant citation. It is the authors' responsibility that all references are properly cited.

Check thoroughly to make sure:
if paper titles are in lower case (L705,etc),
(this journal seems not have regulation of case usage, but follow your majority)
if scientific names are in Italics (L706,etc),
if journal titles are abbreviated when possible (L691,694,etc many),
if abbreviated journal title words accompany a dot (L703,etc),
if book titles are in Italic title case (L701,etc),
etc.

See the citation guide at:
https://www.mdpi.com/authors/references/

 

 

Comments on the Quality of English Language

Check punctuation. 

Author Response

We are thankful to the reviewer whose comments highlighted missing outs and inconsistencies in our manuscript. We have carefully addressed all the comments. Our responses are in red after each comment. All the changes inside the manuscript are also marked in red.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This is a well-written and engaging article that offers valuable insights into oxidative stress parameters in Gammarus lacustris. The study is clearly structured and addresses an important topic, highlighting the role of oxidative stress biomarkers as sensitive indicators of environmental pressure in freshwater ecosystems. The integration of seasonal patterns with hydrophysical and hydrochemical variability across different tributaries strengthens the relevance of the findings. Overall, the work provides useful information for researchers in aquatic ecology and ecotoxicology and represents a meaningful contribution to the monitoring and assessment of anthropogenic impacts in freshwater systems.

Minor comments:

-Methods:

Although 1 nmol/mg protein is equivalent to 1 pmol/μg protein, is the use of nmol MDA per mg protein more common in similar studies?

-Lines 78-79:

We note that the statement “Despite abundant European evidence, ecotoxicological data on Gammarus lacustris in Armenia are scarce” refers to existing studies in Europe but does not include supporting references. We suggest adding appropriate citations on G. lacustris from other European regions. This would help substantiate the claim and provide readers with relevant bibliographic support.

-Lines 248-257:

• It’s better to use parentheses instead of dashes for ranges.
• The DO units should be stated consistently for all rivers

“The pH values changed cyclically during the observed period within the following ranges: the Gavaraget River (7.0–8.35), the Karchaghbyur River (7.2–8.5), and the Argichi River (7.1–8.3) (Table 1). Their average annual values over the three years were 7.76, 8.31, and 7.54, respectively. However, seasonal pH dynamics showed different patterns among the rivers. In the Gavaraget and Karchaghbyur rivers, pH values followed a similar trend and increased from May to October, whereas in the Argichi River they decreased over the same period. Overall, pH values in all three rivers generally fell within the range corresponding to the national criterion for “excellent” water quality (6.5–8.5).

 

Dissolved oxygen (DO) values also changed cyclically during the observed period, within the following ranges: the Gavaraget River (7.8–11.2 mg L⁻¹), the Karchaghbyur River (7.5–9.9 mg L⁻¹), and the Argichi River (8.8–11.2 mg L⁻¹) (Table 1).”

 

-Discussion:

The effect of temperature on stress in Gammarus lacustris has been previously investigated (Vereshchagina et al., 2018). However, this study is not cited in the manuscript. Could the authors clarify whether it provides relevant information for the present study? If so, it should be included in the text.

Vereshchagina K, Kondrateva E, Axenov-Gribanov D, Shatilina Z, Khomich A, Bedulina D, Zadereev E, Timofeyev M. 2018. Nonspecific stress response to temperature increase in Gammarus lacustris Sars with respect to oxygen-limited thermal tolerance concept. PeerJ 6:e5571 https://doi.org/10.7717/peerj.5571.

The authors may consider incorporating the following work (if it provides additional information, at the authors' discretion): Timofeyev, M. A.; Shatilina, Z. M.; Kolesnichenko, A. V.; Bedulina, D. S.; Kolesnichenko, V. V.; Pflugmacher, S.; and Steinberg, C. E. W. (2006), which demonstrates that natural organic matter (NOM) induces oxidative stress in the freshwater amphipods Gammarus lacustris and Gammarus tigrinus (Science of the Total Environment, 366(2–3): 673–681). https://doi.org/10.1016/j.scitotenv.2006.02.003

 

 

Author Response

We are thankful to the reviewer whose comments highlighted missing outs and inconsistencies in our manuscript. We have carefully addressed all the comments. Our responses are in red after each comment. All the changes inside the manuscript are also marked in red.

Author Response File: Author Response.docx