Illustrated Guide to the Main Macroalgae of the Portuguese Continental Atlantic Coast

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General Comments

The manuscript presents an extensive and visually rich field guide to macroalgae of the Portuguese Atlantic coast which is suitable as an educational compendium. However, the manuscript lacks a focused rationale for this particular field guide. Additionally, the work does not provide a critical review of existing identification guides or taxonomic challenges. To merit publication, the manuscript must undergo substantial revision to integrate scientific rigor, provide justification for taxon inclusion, discuss uncertainties in identification, and situate the guide within current research trends in phycology and biodiversity monitoring.

Specific Comments:

1) The introduction provides a general overview of macroalgae, but it lacks a focused rationale for this particular field guide. It does not explain why the Central and Northern Portuguese coast is biologically or ecologically significant. I suggest that the authors provide in the introduction supporting literature or data on biodiversity richness, endemism, or threats in the area.

2) Photographic documentation and herbarium specimens are shown, but no metadata is provided ( such as collector, location, date, voucher numbers). I believe that a field guide should include a section clarifying specimen curation practices.

3) The authors didn’t mention of quality control, taxonomic validation (e.g., through Floras or expert consultation), or whether the taxonomy adheres to current databases like AlgaeBase or WoRMS. I suggest to include these information in the revised manuscript.

4) The guide is visually attractive and potentially useful for students. However, it lacks a consistent structure and scientific rigor expected in peer-reviewed literature: (a) the illustrations are not consistently labeled with scale bars; and (b) No dichotomous or matrix key is provided to assist in field identification. I suggest to include these information in the revised manuscript.

5) Habitat descriptions of the seaweed given by the authors are anecdotal and lack citations. Also, more ecological context should be provided (such as indicator species for pollution, role in trophic webs, etc.).

Comments on the Quality of English Language

The English could be improved to more clearly express the research. I still saw some grammatical errors in the manuscript. 

Author Response

General Comments

The manuscript presents an extensive and visually rich field guide to macroalgae of the Portuguese Atlantic coast which is suitable as an educational compendium. However, the manuscript lacks a focused rationale for this particular field guide. Additionally, the work does not provide a critical review of existing identification guides or taxonomic challenges. To merit publication, the manuscript must undergo substantial revision to integrate scientific rigor, provide justification for taxon inclusion, discuss uncertainties in identification, and situate the guide within current research trends in phycology and biodiversity monitoring.

Author's response: I am very grateful for the comments made and, especially, the suggestions for corrections/improvements, which will indeed be useful in the process of revising this guide.

Specific Comments:

1) The introduction provides a general overview of macroalgae, but it lacks a focused rationale for this particular field guide. It does not explain why the Central and Northern Portuguese coast is biologically or ecologically significant. I suggest that the authors provide in the introduction supporting literature or data on biodiversity richness, endemism, or threats in the area.

Author's response: The following text has been added to the guide's introduction: “The ecological richness of the Central and Northern Portuguese coast is reflected in the high diversity of macroalgal species it supports, many of which are endemic or hold biogeographic significance within the Atlantic realm. This richness, however, exists alongside pronounced vulnerability—pressures from climate change, invasive species, and anthropogenic impacts threaten the integrity of coastal habitats and the delicate balance of macroalgal communities. As such, documenting and monitoring this biodiversity is not only scientifically valuable but also vital for conservation efforts and informed coastal management.”

Additionally, I have changed the title of the Guide to "Illustrated Guide to Macroalgae of the Atlantic Coast of Continental Portugal", based on requests from the three reviewers and the Academic Editor.

2) Photographic documentation and herbarium specimens are shown, but no metadata is provided ( such as collector, location, date, voucher numbers). I believe that a field guide should include a section clarifying specimen curation practices.

Author's response: Information regarding the collector, location, date, voucher numbers, can be found on the Portuguese Seaweeds Website (MACOI) Portal indicated in the guide (http://www.flordeutopia.pt/macoi/), as indicated in the guide.

3) The authors didn’t mention of quality control, taxonomic validation (e.g., through Floras or expert consultation), or whether the taxonomy adheres to current databases like AlgaeBase or WoRMS. I suggest to include these information in the revised manuscript.

Author's response: In The final section of this guide lists all bibliography and sources used in its preparation, namely AlgaeBase, WoRMS, etc.:

 References Consulted

1. Pereira, L., Illustrated Guide to Macroalgae - Knowing and Recognizing Some Species of Portuguese Flora, Coimbra University Press: Coimbra, Portugal, 2009; 90 p. http://dx.doi.org/10.14195/978-989-26-0397-1
2. Gaspar, R.; FONSECA, R.; Pereira, L., Illustrated Guide to the Macroalgae of Buarcos Bay, Figueira da Foz, Portugal, University of Coimbra, Portugal, 2020; 130 p. http://dx.doi.org/10.13140/RG.2.2.31009.56165
3. Bunker, F.; Brodie, J.; Maggs, C.; Bunker, A., Guide to Seaweeds of Britain and Ireland, 2nd ed., Seasearch, Priceton University Press, New Jersey, USA, 2017; 312 p. ISBN: 978-0-948150-51-7
4. Cbioac'h, J.; Cabioc'h, J.Y.; LeToquin, A.; Boudouresuque, C.-F.; Meinesz, A.; Verlauque, M., Guide to algae in the seas of Europe: Atlantic and Mediterranean. Ed. Omega, Barcelona, 2007; 249 p. ISBN: 9788428214476
5. Braune, W.; Michael, D.G. Seaweeds. A Color Guide to Common Benthic Green, Brown, and Red Algae of the World’s Oceans, Ed. Gantner Verlag K.G., Konigstein, Germany, 2011; 601 p. ISBN: 978-3-906166-90-2
6. Pereira, L., Therapeutic and Nutritional Uses of Algae. Science Publishers’ (SP), An Imprint of CRC Press / Taylor & Francis Group, Boca Raton, FL. 560 p. ISBN 9781498755382, http://dx.doi.org/10.1201/9781315152844
7. Pereira, L., Edible Seaweeds of the World, 1st ed., CRC Press, Boca Raton, FL, 2016; 442 p. ISBN: 9-781498-73047, http://dx.doi.org/10.1201/b19970
8. Pereira, L. Littoral of Viana do Castelo—ALGAE (Bilingual). Viana do Castelo City Council, Portugal, 2010; 68 pp.
9. Pereira, L. Littoral of Viana do Castelo—ALGAE. Uses in Agriculture, Gastronomy and Food Industry (Bilingual). Viana do Castelo City Council, VC, Portugal, 2010; 68 pp.
10. Pereira, L. Portuguese Seaweeds Website (MACOI). University of Coimbra, Portugal. Available online: http://www.flordeutopia.pt/macoi/default.php (accessed June 17, 2025).
11. Guiry, M.D. National University of Ireland, Galway. Available online: https://www.algaebase.org/ (accessed June 18, 2025).

 

Additionally, the following bibliographical references have been added to reduce the proportion of sources from the author of this guide. I would like to emphasize, however, that this high number of bibliographical sources from the author of this guide is due to the fact that in Portugal, most publications on this topic are by Leonel Pereira, as you can easily see by simply searching for "algae/seaweeds + Portugal".

Additional Bibliography:

Harvey, W.H. 1846-1851. Phycologia Britânica. Several Volumes. Reeve & Benham, London.

 

4) The guide is visually attractive and potentially useful for students. However, it lacks consistent structure and scientific rigor expected in peer-reviewed literature: (a) the illustrations are not consistently labeled with scale bars; and (b) No dichotomous or matrix key is provided to assist in field identification. I suggest to include these information in the revised manuscript.

Author's response: Since this is an illustrated guide, based on previously published guides (see bibliographic list), it is not part of my strategy for this guide to be a dichotomous research key, as this type of literature has already been published previously (see bibliographic list). The objective of this work was to create a simple to use guide, with identifications based fundamentally on images, and short descriptive texts of each species.

Regarding the type of scale used, in most cases, photos were taken of herbarium specimens using a paper scale. In photos taken underwater, or in rocky coastal areas, the scale is usually my hand or other objects with known dimensions.

5) Habitat descriptions of the seaweed given by the authors are anecdotal and lack citations. Also, more ecological context should be provided (such as indicator species for pollution, role in trophic webs, etc.).

Author's response: The "Habitat" information is as simple and direct as possible, as this work is a practical and visual identification guide, not an exhaustive compendium on the algal flora of Portugal, and its ecology.

Comments on the Quality of English Language

The English could be improved to more clearly express the research. I still saw some grammatical errors in the manuscript. 

Author's response: A review of the text was carried out at the grammar and English level

 

Reviewer 2 Report

Comments and Suggestions for Authors

The author should reorganize the manuscript keeping in mind that the manuscript is an illustrated guide. It is not easy to identify species by using only pictures, and considering only color and morphology. Many characters are visible only under microscope. Without an identification key and a microscope it is probably possible recognize some genera but certainly not species. The author should indicate the references used to identify the species and for the taxonomic update. In some Figures scale bars are missing. The author should check the manuscript very carefully, for both english and mistakes. The author should also check very carefully the order of species, for instance Hypoglossum hypoglossoides is after Grateloupia turuturu instead of Erythroglossum lusitanicum. In the references there are too many self-citations. The author should report Harvey in the References (there are many figures) and the Herbarium to which the specimen belong to. The author should also check the quality of Figures.

Some specific comments

Title: please, change as macroalgae and eliminate Identification. In the manuscript there are not Identification keys but only the morphological descriptions of the species

Line 18. please, change as “and it is eventually reported (by an illustrated icon) if it has a potential use by human being and if it is a non-indigenous species.”

Line 20. “main taxonomic group to which they belong (green, brown or red macroalgae).” These are not taxonomic groups

Lines 21-24. Please, anticipate this part and rewrite it to avoid repetitions

Keywords: Heterokontophyta instead of Phaeophyceae

Lines 28-93. Please, rewrite, reorder and avoid repetitions. It could be useful to add a Figure for morphological types

Line 37. Please, eliminate taxonomic (see comments of Line 20)

Line 57. Please, add tannins

Line 64. Please, change as morphological

Line 72. Please, eliminate “a”

Line 169. Please, move Figure 3 from Line 169 to Line 132. In the manuscript there isn’t a section referring to Non-indigenous species, please add a section that refer to this icon present in Figure 3

Line 175. Please, change as Illustrated guide

Figure 7. Filamentous (Figure 7) is redundant, please only one (apply the same to all the Figures)

Line 271. You are indicating only one of the synonyms, specify that in the Introduction for instance

Line 566. Please, eliminate one of the two icons

Line 598. Please, after a punctuation Ulva rigida

Line 831. Please, add green

Lines 835, 866, 1946. Please, eliminate Família

Lines 1347, 1611. Please, change as Sargassaceae

Line 1462. Please, eliminate one of the two Order:

Lines 1610, 1639, 1677, 3402, 3432. Please, change as Order:

Lines 1967, 3563. Please, eliminate Classification

Lines 2540, 3722. synonym is missing

Lines 2691, 2725. Please, change as Wrangeliaceae

Line 3356. Please, change as (Turner) Kützing

Line 3612. Please, change as Family: Scinaiaceae

Line 3722. Please, eliminate Habitat

Line 4109. Please, change as Family: Grateloupiaceae

Lines 4383, 4407. Please, change as Order: Plocamiales

Line 4836. Please, change as Neopyropia leucosticta (Thuret) L.-E.Yang & J.Brodie 2020  (synonym Pyropia leucosticta (Thuret) Neefus & J.Brodie 2011)

Line 5160. Please, change as Order: Hapalidiales; Family: Hapalidiaceae

Line 5251. Please, put it in the right position

Line 5265. Please, put it in the right position

Line 5273. Please, put it in the right position

Line 5284. Please, put it in the right position

Lines 5289-5292. Please, put it in the right position

Line 5300. Please, put it in the right position

Lines 5305-5306. Please, put it in the right position

Line 5309. Please, put it in the right position

Line 5314. Please, put it in the right position

Line 5329. Please, put it in the right position

Comments on the Quality of English Language

I suggest to carefully check the quality of english

Author Response

The author should reorganize the manuscript keeping in mind that the manuscript is an illustrated guide. It is not easy to identify species by using only pictures, and considering only color and morphology. Many characters are visible only under microscope. Without an identification key and a microscope it is probably possible recognize some genera but certainly not species. The author should indicate the references used to identify the species and for the taxonomic update.

Author's response: I am very grateful for the comments made and, especially, the suggestions for corrections/improvements, which will indeed be useful in the process of revising this guide.

Since this is an illustrated guide, based on previously published guides (see bibliographic list), it is not part of my strategy for this guide to be a dichotomous research key, as this type of literature has already been published previously (see bibliographic list). The objective of this work was to create a simple to use guide, with identifications based fundamentally on images, and short descriptive texts of each species.

In some cases, where identification would involve microscopic observations, photos taken using a microscope and/or magnifying glass were added.

In some Figures scale bars are missing. The author should check the manuscript very carefully, for both english and mistakes. 

Author's response: Any missing scales were checked and added when possible. Regarding the type of scale used, in most cases, photos of herbarium specimens were taken using a paper scale. In photos taken underwater or in rocky coastal areas, the scale is usually my hand or other objects with known dimensions.

Harvey's illustrations, for example, are not scaled, so for ethical reasons I should not alter the illustrations by adding a scale.

The author should also check very carefully the order of species, for instance Hypoglossum hypoglossoides is after Grateloupia turuturu instead of Erythroglossum lusitanicum.

Author's response: The sequence was reordered as follows: Erytoglossum lusitanicum, Grateloupia turuturu, and Hypoglossum hypoglossoides

In the references there are too many self-citations.

Author's response: I would like to emphasize that, this high number of bibliographical sources from the author of this guide is due to the fact that in Portugal, most publications on this topic are by Leonel Pereira, as you can easily see by simply searching for "algae/seaweeds + Portugal".

The author should report Harvey in the References (there are many figures) and the Herbarium to which the specimen belong to.

Author's response: The following Bibliographic Reference has been added “Harvey, W.H. 1846-1851. Phycologia Britânica. Several Volumes. Reeve & Benham, London.”

Information regarding the herbarium (MACOI), collector, location, date, voucher numbers, can be found on the Portuguese Seaweeds Website (MACOI) Portal (http://www.flordeutopia.pt/macoi/), as indicated in the guide.

 

The author should also check the quality of Figures.

Author's response: Most images have a resolution of 300 dpi. However, some of the images provided by Prof. Ignácio Bárbara (Coruña University, Galicia, Spain) only have a resolution of 100 to 200 dpi, so there is no chance of improving quality.

 

Some specific comments

Title: please, change as macroalgae and eliminate Identification. In the manuscript there are not Identification keys but only the morphological descriptions of the species

Author's response - The corrected title is: “Illustrated Guide to Macroalgae of the Atlantic Coast of Continental Portugal”

Line 18. please, change as “and it is eventually reported (by an illustrated icon) if it has a potential use by human being and if it is a non-indigenous species.”

Author's response: Done.

Line 20. “main taxonomic group to which they belong (green, brown or red macroalgae).” These are not taxonomic groups

Author's response: corrected for  “Each species is categorized as green, brown, or red macroalgae.”

Lines 21-24. Please, anticipate this part and rewrite it to avoid repetitions

Author's response: Done

Keywords: Heterokontophyta instead of Phaeophyceae

Author's response: Done

Lines 28-93. Please, rewrite, reorder and avoid repetitions. It could be useful to add a Figure for morphological types

Author's response: New information has been added based on comments from the three reviewers and the Academic Editor.

Line 37. Please, eliminate taxonomic (see comments of Line 20)

Author's response: To avoid duplication of information, this sentence has been removed.

Line 57. Please, add tannins

Author's response: Done

Line 64. Please, change as morphological

Author's response: Done.

Line 72. Please, eliminate “a”

Author's response: Done.

Line 169. Please, move Figure 3 from Line 169 to Line 132. In the manuscript there isn’t a section referring to Non-indigenous species, please add a section that refer to this icon present in Figure 3

Author's response: Done.

And

The following paragraph was added to the introduction: “and it is eventually reported (by an illustrated icon) if it has a potential use by human being and if it is a non-indigenous species…”

Line 175. Please, change as Illustrated guide

Author's response: Done.

Figure 7. Filamentous (Figure 7) is redundant, please only one (apply the same to all the Figures)

Author's response: Done.

Line 271. You are indicating only one of the synonyms, specify that in the Introduction for instance

The following paragraph was added: “This guide provides the valid name and its authority, the order, the family, one of the synonyms, the common names (if any), the habitat and a brief description of the main species present on the Portuguese coast.”

Line 566. Please, eliminate one of the two icons

Author's response: Done.

Line 598. Please, after a punctuation Ulva rigida

Author's response: Done.

Line 831. Please, add green

Author's response: Done.

Lines 835, 866, 1946. Please, eliminate Família

Author's response: Done.

Lines 1347, 1611. Please, change as Sargassaceae

Author's response: Done.

Line 1462. Please, eliminate one of the two Order:

Author's response: Done.

Lines 1610, 1639, 1677, 3402, 3432. Please, change as Order:

Author's response: Done.

Lines 1967, 3563. Please, eliminate Classification

Author's response: Done.

Lines 2540, 3722. synonym is missing

Author’s response: According to Algaebase, these species do not have synonyms.

Lines 2691, 2725. Please, change as Wrangeliaceae

Author's response: Done.

Line 3356. Please, change as (Turner) Kützing

Author's response: Done.

Line 3612. Please, change as Family: Scinaiaceae

Author's response: Done.

Line 3722. Please, eliminate Habitat

Author's response: Done.

Line 4109. Please, change as Family: Grateloupiaceae

Author's response: Done.

Lines 4383, 4407. Please, change as Order: Plocamiales

Author's response: Done.

Line 4836. Please, change as Neopyropia leucosticta (Thuret) L.-E.Yang & J.Brodie 2020  (synonym Pyropia leucosticta (Thuret) Neefus & J.Brodie 2011)

Author's response: The suggested correction was made, so I had to change the position of this species in the correct sequence in alphabetical terms.

Line 5160. Please, change as Order: Hapalidiales; Family: Hapalidiaceae

Author's response: Done.

Line 5251. Please, put it in the right position

Line 5265. Please, put it in the right position

Line 5273. Please, put it in the right position

Line 5284. Please, put it in the right position

Lines 5289-5292. Please, put it in the right position

Line 5300. Please, put it in the right position

Lines 5305-5306. Please, put it in the right position

Line 5309. Please, put it in the right position

Line 5314. Please, put it in the right position

Line 5329. Please, put it in the right position

Author's response: All Done.

 

 

Reviewer 3 Report

Comments and Suggestions for Authors

 

The manuscript presents a complete and visually attractive manual to the identity of macroalgae alongside the significant and northerly Atlantic coast of Portugal. The inclusion of exact morphological descriptions, habitat statistics, and potential uses provides full-size realistic value for each researchers and the overall public. The shape of the manual is logical and smooth to comply with, beginning with heritage records on macroalgae, observed by means of targeted identity keys and illustrations. This method is effective for both instructional and field use. The use of illustrated icons to indicate ability human makes use of and the fame of non-indigenous species is a beneficial feature that complements the usability of the manual. I therefore propose suggestion of a major revision for this manuscript prior to acceptance.

General Comments

• Illustrations and Visual Aids: The inclusion of coloration figures, illustrated icons for makes use of and non-indigenous status, and distinct diagrams substantially complements the manual’s accessibility and realistic fee.
• Identification Key: The illustrated identification key is consumer-friendly and logically organized, supporting readers navigate the complexity of macroalgae identity.
• Consistency: Ensure regular use of medical terminology (e.g., usually italicize Latin names, make clear taxonomic terms at the start use).
• Figures and Formatting: All figures need to be of excessive resolution and absolutely labeled. Consider adding scale bars to pictures for higher discipline reference.
• Species Accounts: For every species, encompass distinguishing features, typical habitat, length range, and applicable icons. Highlight variations with similar species to aid identification.

Specific Suggestions:

• Ensure that each one taxonomic terms and morphological descriptors are used continually all through the textual content. For instance, the terms "thallus" and "frond" are both used to describe macroalgal our bodies; bear in mind clarifying these terms at first mention and the use of them continually thereafter.
• Some sections, including the explanation of pigmentary composition and taxonomic class, should gain from clearer subheadings or bullet factors to improve readability.
• The figures referenced (e.g., Figures 1–6) are crucial for expertise branching kinds, colour, and zonation. Ensure that each one figures are actually categorized and of excessive decision for print and digital codecs.
• Consider including scale bars to photographs of macroalgae to offer a feel of size that is in particular beneficial for subject identification.
• The illustrated identification secret's a strong point of the manual. To similarly assist customers, don't forget such as a flowchart or decision tree format at the beginning of the key phase, that can assist users navigate the identity procedure extra efficiently.
• For species which are tough to differentiate visually (e.g., some pink and brown algae), provide additional distinguishing features together with texture, habitat alternatives, or microscopic traits where relevant.
• The segment at the makes use of macroalgae is informative and well-based. To enhance this phase, don't forget including recent statistics or references on the monetary importance of unique species in the place, or case research of local programs in food, agriculture, or industry.
• Where medicinal or pharmaceutical uses are mentioned, clarify whether these are primarily based on traditional knowledge, scientific studies, or each.
• Line 13: “most relevant macroalgae species” – consider “most representative” or “most common and ecologically significant” for precision.
• Lines 14–15: The reference to the MACOI website is helpful; ensure the URL is current and accessible.
• Line 19: “main taxonomic group” – good, but consider specifying “major” or “principal” for consistency with scientific terminology.
• Lines 32–40: “They make photosynthesis” – suggest “They perform photosynthesis.”
• Line 48: “Kingdoms Plantae (green and red algae) and Chromista (brown algae)” – this reflects current consensus but note that some taxonomies may differ; perhaps acknowledge this variability.\
• Line 51: “could efficiently absorb red and blue colour while reflecting green colour” – suggest “efficiently absorb red and blue wavelengths, reflecting green.”
• Line 67: “Illustrated Identification Key” – reference to the key is helpful.
• Lines 69–75: The explanation of thallus structure and fixation organs is detailed and accurate.
• Line 75: “Only the large macroalgae presents a more robust fixation part” – suggest “Only large macroalgae present a more robust holdfast.”
• Lines 85–89: The discussion of blade structure and terminology (monostromatic/polistromatic) is useful for readers.
• Lines 104–107: The explanation of adaptation to ecological factors is clear.
• Line 126: “more than the common citizen can imagine” – consider a more formal tone, e.g., “with a wide range of applications.”
• Lines 132–142: The nutritional value and dietary fiber explanation is accurate.
• Line 143: “the use of macroalgae in agriculture as fertilizers is one of the oldest traditional uses” – well stated.
• Lines 148–153: The historical and current industrial uses are well described.
• Lines 154–168: The pharmaceutical and medicinal uses are detailed and supported by examples.
• Lines 176–177: “superficial examination can create some confusion” – consider “may lead to confusion.”
• Lines 178–180: The guidance for identifying green algae is clear.
• Lines 184–186: The explanation for brown algae coloration is accurate.
• Lines 191–192: The note on colour variability in red algae is important for users.

Author Response

The manuscript presents a complete and visually attractive manual to the identity of macroalgae alongside the significant and northerly Atlantic coast of Portugal. The inclusion of exact morphological descriptions, habitat statistics, and potential uses provides full-size realistic value for each researchers and the overall public. The shape of the manual is logical and smooth to comply with, beginning with heritage records on macroalgae, observed by means of targeted identity keys and illustrations. This method is effective for both instructional and field use. The use of illustrated icons to indicate ability human makes use of and the fame of non-indigenous species is a beneficial feature that complements the usability of the manual. I therefore propose suggestion of a major revision for this manuscript prior to acceptance.

General Comments

• Illustrations and Visual Aids: The inclusion of coloration figures, illustrated icons for makes use of and non-indigenous status, and distinct diagrams substantially complements the manual’s accessibility and realistic fee.
• Identification Key: The illustrated identification key is consumer-friendly and logically organized, supporting readers navigate the complexity of macroalgae identity.
• Consistency: Ensure regular use of medical terminology (e.g., usually italicize Latin names, make clear taxonomic terms at the start use).
• Figures and Formatting: All figures need to be of excessive resolution and absolutely labeled. Consider adding scale bars to pictures for higher discipline reference.
• Species Accounts: For every species, encompass distinguishing features, typical habitat, length range, and applicable icons. Highlight variations with similar species to aid identification.

Author’s Comment: I am very grateful for the comments made and, especially, the suggestions for corrections/improvements, which will indeed be useful in the process of revising this guide.

Specific Suggestions:

• Ensure that each one taxonomic terms and morphological descriptors are used continually all through the textual content. For instance, the terms "thallus" and "frond" are both used to describe macroalgal our bodies; bear in mind clarifying these terms at first mention and the use of them continually thereafter.

Author’s Comment: The meanings of both terms are described in the Glossary

• Some sections, including the explanation of pigmentary composition and taxonomic class, should gain from clearer subheadings or bullet factors to improve readability.

Author’s Comment: The Introduction was completely modified with a multi-paragraph introduction, as recommended by the reviewers.

• The figures referenced (e.g., Figures 1–6) are crucial for expertise branching kinds, colour, and zonation. Ensure that each one figures are actually categorized and of excessive decision for print and digital codecs.

Author’s Comment: Most images have a resolution of 300 dpi. However, some of the images provided by Prof. Ignácio Bárbara (Coruña University, Galicia, Spain) only have a resolution of 100 to 200 dpi, so there is no chance of improving quality.

• Consider including scale bars to photographs of macroalgae to offer a feel of size that is in particular beneficial for subject identification.

Author’s Comment: Regarding the type of scale used, in most cases, photos were taken of herbarium specimens using a paper scale. In photos taken underwater, or in rocky coastal areas, the scale is usually my hand or other objects with known dimensions.

• The illustrated identification secret's a strong point of the manual. To similarly assist customers, don't forget such as a flowchart or decision tree format at the beginning of the key phase, that can assist users navigate the identity procedure extra efficiently.

Author's response: Since this is an illustrated guide, based on previously published guides (see bibliographic list), it is not part of my strategy for this guide to be a dichotomous research key, as this type of literature has already been published previously (see bibliographic list). The objective of this work was to create a simple to use guide, with identifications based fundamentally on images, and short descriptive texts of each species.

• For species which are tough to differentiate visually (e.g., some pink and brown algae), provide additional distinguishing features together with texture, habitat alternatives, or microscopic traits where relevant.

Author's response: when possible, images obtained under the microscope were added.

• The segment at the makes use of macroalgae is informative and well-based. To enhance this phase, don't forget including recent statistics or references on the monetary importance of unique species in the place, or case research of local programs in food, agriculture, or industry.

Author's response: Since this is a practical visual identification guide, potential uses are associated with the graphic icons added to each species. Due to the current size of the document, I don't think it's advisable to add more than the graphic icons.

• Where medicinal or pharmaceutical uses are mentioned, clarify whether these are primarily based on traditional knowledge, scientific studies, or each.

Author's response: Since this is a practical visual identification guide, potential uses are associated with the graphic icons added to each species. Due to the current size of the document, I don't think it's advisable to add more than the graphic icons.

• Line 13: “most relevant macroalgae species” – consider “most representative” or “most common and ecologically significant” for precision.

Author's response: Done.

• Lines 14–15: The reference to the MACOI website is helpful; ensure the URL is current and accessible.

Author's response: The web address is correct and functional.

• Line 19: “main taxonomic group” – good, but consider specifying “major” or “principal” for consistency with scientific terminology.

Author's response: The text was completely modified according to the recommendations of the three reviewers.

• Lines 32–40: “They make photosynthesis” – suggest “They perform photosynthesis.”

Author's response: Done.

• Line 48: “Kingdoms Plantae (green and red algae) and Chromista (brown algae)” – this reflects current consensus but note that some taxonomies may differ; perhaps acknowledge this variability.\

Author's response: I believe there is widespread consensus on this issue.

• Line 51: “could efficiently absorb red and blue colour while reflecting green colour” – suggest “efficiently absorb red and blue wavelengths, reflecting green.”

Author's response: This part of the text has been completely modified based on the comments of the three reviewers.

• Line 67: “Illustrated Identification Key” – reference to the key is helpful.

Author's response: This part of the text has been completely modified based on the comments of the three reviewers.

• Lines 69–75: The explanation of thallus structure and fixation organs is detailed and accurate.

Author's response: Thank you for thr commrnt

• Line 75: “Only the large macroalgae presents a more robust fixation part” – suggest “Only large macroalgae present a more robust holdfast.”

Author's response: Done.

• Lines 85–89: The discussion of blade structure and terminology (monostromatic/polistromatic) is useful for readers.

Author's response: Thank you for the comment

• Lines 104–107: The explanation of adaptation to ecological factors is clear.

Author's response: Thank you for the comment

• Line 126: “more than the common citizen can imagine” – consider a more formal tone, e.g., “with a wide range of applications.”

Author's response: Done.

• Lines 132–142: The nutritional value and dietary fiber explanation is accurate.

Author's response: Thank you for the comment

• Line 143: “the use of macroalgae in agriculture as fertilizers is one of the oldest traditional uses” – well stated.

Author's response: Thank you for the comment

• Lines 148–153: The historical and current industrial uses are well described.

Author's response: Thank you for the comment

• Lines 154–168: The pharmaceutical and medicinal uses are detailed and supported by examples.

Author's response: Thank you for the comment

• Lines 176–177: “superficial examination can create some confusion” – consider “may lead to confusion.”

Author's response: Done.

• Lines 178–180: The guidance for identifying green algae is clear.

Author's response: Thank you for the comment

• Lines 184–186: The explanation for brown algae coloration is accurate.

Author's response: Thank you for the comment

• Lines 191–192: The note on colour variability in red algae is important for users.

Author's response: Thank you for the comment

 

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors revised the paper following my suggestions and recommendation. Thus, the paper is now acceptable for publication. 

Author Response

Dear Reviewer thank you for the suggested corrections

 

 

Reviewer 2 Report

Comments and Suggestions for Authors

As I said in the previous review, this is not an identification key but only an illustrated guide. An Identification key is a tool that allows us to identify a specimen through a careful analysis of the characters by using a microscope. Many characters are visible only under microscope and very often it is necessary to make a cross-section. It is not easy to identify species by using only pictures, considering only the color and the morphology. You can probably recognize some genera but certainly not species. Indeed, many photos show characters visible only under microscope. There are still some mistakes in the manuscript and the Introduction should be re-written (also the added paragraph), as I said in the previous review. Several repetitions exist. As highlighted by the numerous photos taken under a microscope, it should be clarified that for the identification of the macroalgae the use of a microscope is fundamental. In this practical illustrated guide, it would have been useful to know the ecological role and the health status of macroalgae, if they are endemic and if they are threatened in addition to their uses. In a practical guide, drawings and pictures of herbaria specimens are not very useful. Many photos are not good. The author should indicate in the text the references used for the taxonomic update and the synonyms. The author should also add that a Glossary is present. The style of References should be carefully checked. To avoid a high number of self-citations, it could be reported only the recent papers that certainly report the old ones in the References, adding for instance  “and references herein”. Example [23 and references herein]

Some specific comments

Line 38. “conservation significance” but there is not information about the conservation significance of the macroalgae

Line 88. There is not any reference to taxonomy in this paragraph

Line 125. The “Illustrated Identification Key” in this guide. An identification key is not present

Lines 128-131. “The thallus of macroalgae is divided into the frond, the upright part, consisting of the stipe and the blade, and the normally discrete fixation organ, in the form of a small disk or a tuft of fine, elongated, colorless elements, called rhizoids.” It is not always true

After the paragraph 1.4. The Habitat of Rocky Shores the author should add another one on Non-indigenous species in order to justify the icon reported in the Figure 3. It is not enough to add Non-indigenous species in the legend

Paragraph 2.1.

Filamentous.

Figure 7. Filamentous macroalgae

As I said in the previous review, It is redundant to put both (this applies from Figure 7 to Figure 20)

Line 669. Synonyms: Ulva fasciata Delile 1813; Ulva crassa Kjellman 1877; Ulva rotundata Bliding 1969. Only one synonym as reported in Line 232

Lines 1213-1214. Synonyms: Dictyopteris membranacea Batters 1902; Dictyopteris ambigua (Clemente) Cremades 1990. Only one synonym as reported in Line 232

Line 2084. Colpomenia peregrina Sauvageau 1927. The synonym is missing

Lines 2212-2213. tetrasporophyte phase, known as the “Falkenbergia-phase” (tetrasporophyte). That also applies to Asparagopsis taxiformis (Delile) Trevisan 1845

Line 3111. Please, add Boergeseniella thuyoides

Line 3528. Please, change as Gracilaria verrucosa var. procerrima  (Esper) M.P.Reis, nom. inval. 1981: 1414

Lines 4170-4171. Figure 160. a) underwater photo (©MACOI, Leonel Pereira); b) Harvey’s illustration (In Public Domain). Photos are not good

Line 4862. Rhodophyllis divaricata (Stackhouse) Papenfuss 1950  Please, move it before Rhodymenia pseudopalmata (J.V. Lamouroux) P.C. Silva 1952 (Line 4835)

Line5093. Lithophyllum hibernicum. The synonym is missing

Line 5095. Similar species: Lithophyllum incrustans Philippi 1837. Please, move it in the Description

Lines 5335-5337. Year is missing

Lines 5351-5352. Year is missing

 

Comments on the Quality of English Language

English could be improved

Author Response

Reviewer 2: As I said in the previous review, this is not an identification key but only an illustrated guide. An Identification key is a tool that allows us to identify a specimen through a careful analysis of the characters by using a microscope. Many characters are visible only under microscope and very often it is necessary to make a cross-section. It is not easy to identify species by using only pictures, considering only the color and the morphology. You can probably recognize some genera but certainly not species. Indeed, many photos show characters visible only under microscope.

Author comment: I appreciate comments (when constructive and to improve this guide)

The author didn't intend to write an identification key, but rather a simple illustrated identification guide, practical and easy to use for non-specialists in seaweed identification.

Therefore, all the suggestions made would be useful for a Dichotomous Identification Key, which was never my intention!

All images used are available, some of which are original or provided by third parties. The image resolutions are those available and correspond to those kindly provided by Prof. Ignácio Bárbara (retired Professor of the University of A Coruña, Galicia, Spain). Therefore, using available resources, all images were processed to achieve the best possible resolution.

 

Reviewer 2: There are still some mistakes in the manuscript and the Introduction should be re-written (also the added paragraph), as I said in the previous review. Several repetitions exist. As highlighted by the numerous photos taken under a microscope, it should be clarified that for the identification of the macroalgae the use of a microscope is fundamental. In this practical illustrated guide, it would have been useful to know the ecological role and the health status of macroalgae, if they are endemic and if they are threatened in addition to their uses. In a practical guide, drawings and pictures of herbaria specimens are not very useful.

Author comment: Unfortunately, I disagree with your comment. I reiterate that this guide was never intended to be an exhaustive treatise on the characterization and identification of macroalgae, but merely a useful and practical guide for biology and natural science students.

 

Reviewer 2: Many photos are not good. The author should indicate in the text the references used for the taxonomic update and the synonyms.

Author comment: All images used are available, some of which are original or provided by third parties. The image resolutions are those available and correspond to those kindly provided by Prof. Ignácio Bárbara (retired Professor of the University of A Coruña, Galicia, Spain). Therefore, using available resources, all images were processed to achieve the best possible resolution.

 

Reviewer 2: The author should also add that a Glossary is present.

Author comment: A section (nº 7) called Glossary has been added, as suggested.

 

 Reviewer 2: The style of References should be carefully checked. To avoid a high number of self-citations, it could be reported only the recent papers that certainly report the old ones in the References, adding for instance “and references herein”. Example [23 and references herein]

Author comment: The bibliographical references have all been adjusted to the MDPI style. The fact that there are many self-citations is easily explained, as I am the author or co-author of the few published guides and keys on the macroalgal flora of Portugal.

 

Reviewer 2:  Some specific comments

Line 38. “conservation significance” but there is not information about the c significance of the macroalgae

Author comment: The word "conservation" has been removed from the text

 

Line 88. There is not any reference to taxonomy in this paragraph

Author comment: Reference has been added

Line 125. The “Illustrated Identification Key” in this guide. An identification key is not present

Author comment: The word "key" has been removed from the text

 

Lines 128-131. “The thallus of macroalgae is divided into the frond, the upright part, consisting of the stipe and the blade, and the normally discrete fixation organ, in the form of a small disk or a tuft of f ine, elongated, colorless elements, called rhizoids.” It is not always true

Author comment: The thallus of some macroalgae is divided into the frond, the upright part, consisting of the stipe and the blade, and the normally discrete fixation organ, in the form of a small disk or a tuft of fine, elongated, colorless elements, called rhizoids. Only large macroalgae presents a more robust fixation part, composed of more or less curved elements, the hapteron (Note: The word "some" was added)

 

After the paragraph 1.4. The Habitat of Rocky Shores the author should add another one on Non indigenous species in order to justify the icon reported in the Figure 3. It is not enough to add Non indigenous species in the legend

Author comment: Was added this paragraph “1.5. Non-Indigenous Algae on the Western Portuguese Coast

The western Portuguese coast has seen the introduction of several non-indigenous algal species, primarily through maritime activities and aquaculture. Among the most notable are Asparagopsis armata (Rhodophyta) and Sargassum muticum (Phaeophyceae), which have established themselves in intertidal and subtidal zones. These invasive species can outcompete native flora, alter habitat structures, and impact local biodiversity. Their presence highlights the need for ongoing monitoring and management strategies to mitigate ecological disruption and preserve the integrity of coastal marine ecosystems [13].”

 

Paragraph 2.1. Filamentous. Figure 7. Filamentous macroalgae As I said in the previous review, It is redundant to put both (this applies from Figure 7 to Figure 20)

Author comment: Thanks for the comment, but I don't agree that it's redundant. The purpose of this paragraph is to illustrate the different types of thalli with some examples.

 

Line 669. Synonyms: Ulva fasciata Delile 1813; Ulva crassa Kjellman 1877; Ulva rotundata Bliding 1969. Only one synonym as reported in Line 232

Author comment: The purpose of indicating at least one synonym is to prevent the possibility that in some older literature, some species may be identified with names that are currently synonymous.

 

Lines 1213-1214.

Author comment: The same as Line 669

 

Line 2084. Colpomenia peregrina Sauvageau 1927. The synonym is missing

Author comment: Added “Colpomenia sinuosa var. peregrina Sauvageau 1927
Colpomenia peregrina (Sauvageau) Hamel 1937”

 

Lines 2212-2213. tetrasporophyte phase, known as the “Falkenbergia-phase” (tetrasporophyte). That also applies to Asparagopsis taxiformis (Delile) Trevisan 1845

Author comment: Added “In the “Falkenbergia-phase” (tetrasporophyte), tetrasporangia appear singly…”

 

Line 3111. Please, add Boergeseniella thuyoides

Author comment: Done.

 

Line 3528. Please, change as Gracilaria verrucosa var. procerrima (Esper) M.P. Reis, nom. inval. 1981: 1414

Author comment: Done.

 

Lines 4170-4171. Figure 160. a) underwater photo (©MACOI, Leonel Pereira); b) Harvey’s illustration (In Public Domain). Photos are not good

Author comment: The photo of this species was replaced by a better quality one taken by Prof. Ignácio Bárbara.

New legend: Figure 160. a) underwater photo (©Ignácio Bárbara; b) Harvey’s illustration (In Public Domain).

 

Line 4862. Rhodophyllis divaricata (Stackhouse) Papenfuss 1950 Please, move it before Rhodymenia pseudopalmata (J.V. Lamouroux) P.C. Silva 1952 (Line 4835)

Author comment: Done

 

Line 5093. Lithophyllum hibernicum. The synonym is missing

Author comment: Corrected with the addition: Synonyms: Lithophyllum fasciculatum f. subtile (Foslie) Foslie 1897; Lithothamnion fasciculatum f. subtile Foslie 1897

 

Line 5095. Similar species: Lithophyllum incrustans Philippi 1837. Please, move it in the Description

Author comment: Done

 

Lines 5335-5337. Year is missing

 Lines 5351-5352. Year is missing

Author comment: corrected

Final note: Thank you for all corrections and suggestions made.

 

Reviewer 3 Report

Comments and Suggestions for Authors

Authors have successfully addressed my previous comments.

Author Response

Thank you for all suggested corrections.

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Author,

 I think that the guide should be re-organized mainly taking into consideration the users to whom the guide is addressed, Researchers or common people. Researchers need identification keys and photos (micro and macro) of high quality. Common people don’t have the tools necessary to see the microscopic characters shown in the guide and also need photos macro of good quality. 

The main characters used in this guide are morphology and color. We know that trying to identify macroalgae by using only morphology and color and by the comparison with images (many photos are not of good quality), is not a good scientific method. Drawings and pictures of herbaria specimens are not useful at all.

For the identification of the macroalgae the use of a microscope is fundamental. You included yourself many images showing microscopic characters.

As said in the previous reviews, the self-citation rate is high and not in line with the rules of the Journal. The self-citation rate should be of about 15%.

 

Comments on the Quality of English Language

it could be improved

Author Response

Thank you for your comments. In my view, herbarium specimens are essential for the intended users of this illustrated guide. In many cases, these are the only available reference materials, and they provide a valuable visual resource for both researchers and field technicians. Therefore, I believe that including well-photographed herbarium specimens adds meaningful support to the guide and should be retained alongside field and microscopic images. Regarding the self-citation rate, as previously mentioned, the reason for the high number of self-references is that the most recent and relevant publications on the algal flora of Portugal are predominantly authored by myself. This can be easily verified through a simple bibliographic search. Nonetheless, I will revise the reference list and reduce the self-citation rate to align with the journal’s guidelines, replacing them with independent sources wherever appropriate. As for the microscopic images, many of them are simply not available. Moreover, for non-specialist users, these images are not essential, as the guide is primarily intended to offer practical and accessible identification tools based on external observations.