Three New Nitzschia (Bacillariophyceae) Species from Highly Acidic Artificial Lakes in Çanakkale, Türkiye

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Among the natural freshwater environments, studies on diatoms that are naturally distributed in the special habitat of the mining area is very limited, and it is judged to be a unique research field. It was research content with taxonomic meaning, I have some doubts about whether it matches the scope of this Journal. I found the Introduction to be well written aside from some major wording issues. (These wording issues appear throughout the text, so some careful editing is in order.). I found the Results section to be hard to follow. It would benefit from a careful reorganization and more precise wording.

Several issues require more elaboration form the authors for the paper to become even more relevant and useful: the current findings should be placed into the context of literature globally published on the topic, and finally recommendations for the future studies could be refined.

In addition, it is hoped that the ecological and limnological comparison of the three types of diatoms that appeared in the objective of this MS will be supplemented in more detail in the results section or discussion section.

Specific comments:

Abstract

The abstract might give us some hints for statistic and numeric data in the part of the end of line.

L22-23: Please give us one sentence for major conclusions in the last paragraphs of abstract.

L24: Nitzschia. à Nitzschia

Introduction

Introduction was well written and nicely leads the reader towards except research main questions. Literature has been comprehensively used and need current literatures. I would like to mention what is the more fundamental reason for the investigation of the diatom species that appeared due to the peculiarity of the mining area. How would you like to think about what kind of information ecologically provides to researchers and readers through this MS and include it in the Introduction?

Materials and Methods

L68-69: Is there a reason why the sample period and intervals were not constant and the survey was conducted 5 times over 3 years?

Results

In the results sections, please include detailed limnological information for the study sites in tables etc.

Comments on the Quality of English Language

 It was research content with taxonomic meaning, I have some doubts about whether it matches the scope of this Journal. I found the Introduction to be well written aside from some major wording issues. (These wording issues appear throughout the text, so some careful editing is in order.). I found the Results section to be hard to follow. It would benefit from a careful reorganization and more precise wording. 

Author Response

We would like to thank to the reviewers for the reading of our manuscript attentionally, paying attention to the draft, their useful comments, suggestions, and contributions.

- Major conclusion was given by adding numeric data was added at the end of the abstract.

Please kindly find all corrections in the report attached.

Please kindly find the corrected version attached.

Kind regards

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Comments on water-2530724 entitled “Three new Nitzschia (Bacillariophyceae) species from highly acidic artificial lakes in Çanakkale, Türkiye”

 This manuscript presents description of three new species of diatoms, Nitzschia arslaniana, N. efeiana and N. szaboiana, isolated from highly acidic artificial lakes in Çanakkale, Türkiye. An analysis of these taxa has been carried out using study of morphology, ultrastructure and phenotypic plasticity only. I have some suggestions for improving this manuscript.

 Three new species of Nitzschia were described using morphology data only. According to study of Mann et al. (2021) using integrative approach (light and scanning electron microscopy, molecular genetic analysis), the genus Nitzschia is non-monophyletic. Several of the main clades and subclades are cryptic (lacking morphological synapomorphies) and homoplasy is common in both light microscopical and ultrastructural characters (to the extent that organisms initially assigned to the same species sometimes prove to belong to a different main clade). Nevertheless, some characters, including the structure of the raphe canal and girdle, seem to be sufficiently conservative evolutionarily to give a provisional estimate of relationships if molecular data are unavailable.

But the authors of the manuscript, when describing new species, did not use molecular genetic analysis and did not analyze the raphe canal and girdle of the studied strains. Therefore, they should study these diatoms using an integrative approach to prove that these strains are new species.

See: Mann, D.G.; Trobajo, R.; Sato, S.; Li, C.; Witkowski, A.; Rimet, F.; Ashworth, M.P.; Hollands, R.M.; Theriot, E.C. Ripe for reassessment: A synthesis of available molecular data for the speciose diatom family Bacillariaceae. Mol. Phylogenetics Evol. 2021, 158, 106985. https://doi.org/10.1016/j.ympev.2020.106985

Other minor revisions:

1) Lines 72-73: For a multi-parameter meter the name of the manufacturer, city and country should be given.

2) Line 75: “the entire micosopic slide” should be corrected to “the entire microscopic slide”.

3) Line 85-86: For a light microscope and a camera the name of the manufacturer, city and country should be given.

4) Lines 141, 183, 229: “electolyte conductivity” should be corrected to “electrolyte conductivity”.

          5) Line 366: “Trabajo, R.” should be corrected to “Trobajo, R.”.

Comments for author File: Comments.pdf

Author Response

We would like to thank to the reviewers for the reading of our manuscript attentionally, paying attention to the draft, their useful comments, suggestions, and contributions.

Thank you for the comments and corrections to our manuscript. Addressing issues around the genetics of this genus should be included in the manuscript. We agree that genetic analyses on these new taxa can/should be completed at some point, and the results combined with traditional morphological analysis can give a more complete understanding of the systematic position of these taxa. The taxa are considered rare from one extreme environment and difficult to culture. However, we plan to attempt sequencing within the next 2 years as sampling access permits.  At the present time, we have enough morphological information, specifically for the characters you highlight (keel formation, cingulum) that we feel the new species can be resolved using morphological analysis. We would also add the comment that as noted by Mann et al. (2021) there is still a lot of “cryptic” noise and missing data which is needed to better understand the systematics of the genus.  It is quite likely that additional genes may be required to further resolve this issue as presented in Mann et al. (2021)

In the manuscript we added a paragraph in the Introduction (lines 39-49) and comments in the discussion to address potential genetic positions for the new taxa (lines 273-275; 298-300; 327-329). As suggested by the reviewer we have specially highlighted the primary morphological features in the species descriptions and new added data to Table 1. The new additions include comparisons with published type samples (e.g. Trobajo et al. 2013) and additional SEM images from secondary publications including Poulin et al. (1990) and Maidana & Romero (1995).

- Lines 72-73: For a multi-parameter meter the name of the manufacturer, city and country was  given in the text.

- Line 75: “the entire micosopic slide” was corrected as “the entire microscopic slide”.

- Line 85-86: For a light microscope and a camera the name of the manufacturer, city and country was given in the text.

- Lines 141, 183, 229: “electolyte conductivity” was corrected as “electrolyte conductivity”.

- Line 366: “Trabajo, R.” was corrected as “Trobajo, R.”.

Kindly regards

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Comments on water-2530724-peer-review-v2 entitled “Three new Nitzschia (Bacillariophyceae) species from highly acidic artificial lakes in Çanakkale, Türkiye”

 The authors corrected some of the comments. However, they did not use an integrative approach (including molecular genetic analysis) to describe the three new species of Nitzschia in the revised manuscript. But, they unreasonably state that "However, the addition of genetic data in the future will further delineate this acid-loving Nitzschia from other taxa with the same clades" (lines 267-268).

"The four-gene tree shows good support for eight major clades of Bacillariaceae" (Mann et al., 2021). But this tree is not based on "both environment and morphological characters" (lines 278-280, 303-305, 333-334), as authors state.

Thus, they should study these diatoms using an integrative approach (including molecular genetic analysis) to prove that these strains are new species.

Comments for author File: Comments.pdf

Author Response

We would like to thank to the reviewers for the reading of our manuscript attentionally, paying attention to the draft, their useful comments, suggestions, and contributions.

Please kindly find all corrections as attached report.

Author Response File: Author Response.pdf