Volcanic Rejuvenation and Hydrothermal Systems: Implications for Conservation and Resource Assessment in the Southeastern Tyrrhenian Sea

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper conducts a detailed analysis of the geological and geophysical characteristics of the southern Tyrrhenian Sea and identifies multiple areas with potential deep - sea mining value. The methods are rigorous, and the structure is clear. The following are the revision suggestions:

1. The abstract concisely summarizes this study, but it may benefit from a clearer distinction between established ecological protections and potential mining targets.
2. The introduction provides a broad context for deep - sea mining but lacks a focused rationale for why the southeastern Tyrrhenian Sea is a unique case study.
3. In the geological background section, it is recommended to briefly summarize the geological history and pay more attention to aspects directly related to hydrothermal vents.
4. The study technically describes the use of the Analytic Signal (AS) tool, but the geological significance of demagnetized zones has not been fully explored. In particular, the connection between magnetic signatures and specific mineral types is implicit rather than explicit.
5. The section on regulatory and environmental context outlines Italian and international regulations but does not analyze the conflicts or synergies between them.
6. The discussion section lacks specificity, and the discussion of ecological impacts is general. It should link specific geophysical findings to conservation needs. It is recommended to combine with specific policy backgrounds to enhance practicality.
7. The part about future research directions in the conclusion section is slightly brief and could be further expanded.

Author Response

Reviewer #1

 

This paper conducts a detailed analysis of the geological and geophysical characteristics of the southern Tyrrhenian Sea and identifies multiple areas with potential deep - sea mining value. The methods are rigorous, and the structure is clear. The following are the revision suggestions:

We sincerely thank Reviewer #1 for their thorough evaluation and constructive comments. Their valuable feedback has greatly contributed to improving the clarity, rigor, and overall quality of our manuscript. All corrections were made also taking into account the comments of the reviewer #2.

 

Comments 1 - The abstract concisely summarizes this study, but it may benefit from a clearer distinction between established ecological protections and potential mining targets.

Response 1:

The original abstract:

The SE Turrhenian Sea is a Backarc basin characterized by the onset of volcan-ism over the last ca. 11 Ma and the emplacement of a large number of volcanic sea-mounts...

Was revised as follows:

The southeastern Tyrrhenian Sea is a back-arc basin characterized by the onset of volcanism over the past ~11 million years and the development of numerous volcanic seamounts. Hydrothermal venting is predominantly concentrated in the southeastern sector, encompassing the Aeolian volcanic arc and major volcanic edifices such as Palinuro and Marsili. These systems frequently exhibit zones of localized magnetic depletion (demagnetization) within otherwise magnetized volcanic structures, often linked to hydrothermal alteration. Notably, volcanic rejuvenation phases are commonly associated with active hydrothermal circulation.

In response to mounting ecological concerns, the Italian government has delineated extensive Ecological Protection Zones (EPZs), including those in the eastern Tyrrhenian sector. These EPZs encompass a series of prominent seamounts—Palinuro, Marsili, Vercelli, Vavilov, Magnaghi, Enarete, and Anchise—that exhibit morphological evidence of rejuvenation and magnetic anomalies consistent with hydrothermal modification. Such features are indicative of potentially mineralized systems, relevant for future resource exploration.

A comprehensive evaluation of both the ecological significance and the mineral potential of these areas is now imperative. Balancing environmental conservation with the strategic assessment of deep-sea mining prospects will be essential to mitigate biodiversity loss while promoting the sustainable use of marine mineral resources.

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Comments 2 - The introduction provides a broad context for deep - sea mining but lacks a focused rationale for why the southeastern Tyrrhenian Sea is a unique case study.

Response 2 -  Agree. We added the following section to the introduction:

The southeastern Tyrrhenian Sea is a geodynamically unique area, shaped by active back-arc extension above a subducting slab, which has led to the formation of one of the highest concentrations of volcanic seamounts in the Mediterranean. This region hosts hydrothermal systems known to produce polymetallic sulfide deposits rich in copper, zinc, iron, and rare earth elements (REE). Its relatively young seafloor enhances mineral preservation, while its proximity to Europe offers logistical advantages. The overlapping features of tectonic activity, hydrothermal mineralization, and ecological sensitivity make the southeastern Tyrrhenian a natural laboratory for studying the intersection of deep-sea mining potential and marine conservation. The coexistence of ecologically protected and unprotected, yet geologically similar, areas makes it a distinctive setting for evaluating both deep-sea mining potential and conservation priorities.

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Comments 3: In the geological background section, it is recommended to briefly summarize the geological history and pay more attention to aspects directly related to hydrothermal vents.

Response 3: Hydrothermal vents are discussed in detail in the subsequent sections of the manuscript.

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Comments 4 - The study technically describes the use of the Analytic Signal (AS) tool, but the geological significance of demagnetized zones has not been fully explored. In particular, the connection between magnetic signatures and specific mineral types is implicit rather than explicit.

Response 4 – We added the following section in the discussion:

Of course, deep-sea areas potentially eligible for mining activities are more interesting because lesser exposed to environmental damages. In this sense, partially de-magnetized sectors inside magnetic bodies are more interesting because these are the areas presumably affected by demagnetization due to the presence of hydrothermal vents. Crustal demagnetization is a common feature in basalt-hosted hydrothermal vent fields at slow and ultra-slow spreading mid-ocean ridges and caldera hydrothermal areas, primarily due to the removal of magnetic minerals by hydrothermal alteration processes and thermal demagnetization (Bouligand et al., 2014; Tivey et al., 1993)

We also added two specific references:

Bouligand, C., Glen, J., & Blakely, R., 2014. Distribution of buried hydrothermal alteration deduced from high‐resolution magnetic surveys in Yellowstone National Park. JGR: Solid Earth, 119, 2595–2630. https://doi.org/10.1002/2013JB010802

Tivey, M., Rona, P., & Schouten, H., 1993. Reduced crustal magnetization beneath the active sulfide mound, TAG hydrothermal field, Mid-Atlantic Ridge at 26°N. EPSL, 115, 101–115. https://doi.org/10.1016/0012-821X(93)90216-V

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Comments 5 - The section on regulatory and environmental context outlines Italian and international regulations but does not analyze the conflicts or synergies between them.

Response 5 –  Agree. We added the following text to the section 1.3 

Conflicts may arise when economic interests—such as the exploration of mineral-rich hy-drothermal sites—clash with international environmental commitments. For instance, while national laws may authorize marine research and even preliminary resource as-sessments, these may be restricted by broader international obligations to avoid bio-diver-sity degradation or non-compliance with regional conservation targets. Moreover, no spe-cific legal instrument currently exists at either the EU or international level gov-erning deep-sea mining in the Mediterranean, leading to regulatory uncertainty and po-tential ju-risdictional disputes. Nonetheless, synergies also exist. Italy’s EPZs may serve as a model for the integration of marine spatial planning with science-based zoning, in accordance with EU directives such as the Marine Strategy Framework Directive (2008/56/EC) and the EU Biodiversity Strategy for 2030. The alignment between national protective measures and international commitments can enhance policy coherence, espe-cially when conserva-tion areas are designated based on robust geophysical and ecologi-cal criteria, as demon-strated by the findings of this study. In this context, it is significant to recall the official communication sent by the Italian Min-istry of the Environment and Protection of Land and Sea to the EU in 2019, in which Italy committed to the designation of two new Natura 2000 Sites of Community Importance (SCIs) under habitat type 1170 – rocky reefs, specifically for the Palinuro and Vercelli Seamounts. This decision was taken in response to a formal request from the European Union through EUPILOT 8348/16/ENV. This commitment strengthens the ecological sig-nificance of Italy’s EPZs by integrating them into the Natura 2000 Network established under the Habitats Directive (92/43/EEC), and confirms the conservation priority of the Palinuro Seamount over extractive activities such as deep-sea mining. Thus, a more integrated governance framework—one that ex-plicitly links geoscientific data with conservation obligations and resource manage-ment—is urgently needed to balance resource potential and ecosystem vulnerability. This would require stronger coor-dination between national regulatory bodies, scientific insti-tutions, and international or-ganizations to harmonize objectives and avoid conflicting mandates.

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Comments 6 - The discussion section lacks specificity, and the discussion of ecological impacts is general. It should link specific geophysical findings to conservation needs. It is recommended to combine with specific policy backgrounds to enhance practicality.

Response – 6 Agree. We added the following section:

In the southeastern Tyrrhenian Sea, where ecologically sensitive seamounts coincide with hydrothermally active areas, evaluating the environmental impacts of potential deep-sea mining is crucial. Long-term studies (Washburn et al., 2023; Weaver et al., 2022) show that seabed disturbances cause persistent ecological degradation, including sediment plumes that affect regions far beyond the immediate impact zone. Modeling efforts (Martins et al., 2023; Hauton et al., 2017) warn of risks to benthic food webs and metal bioaccumulation, highlighting potential long-term toxicity.

Recent findings by Jones et al. (2025) at a site in the Clarion-Clipperton Zone reveal minimal ecosystem recovery more than 26 years after disturbance. Key benthic organisms, including sponges and invertebrates, remain scarce, and sediment structure has not fully returned. These findings underline the long-lasting ecological damage of deep-sea mining and the need for precautionary frameworks.

Our study emphasizes that magnetic demagnetization and volcanic rejuvenation indicators can help identify hydrothermally altered—and potentially mineral-rich—areas. Yet, these same features often coincide with ecologically valuable habitats. Therefore, an integrated approach to deep-sea policy is urgently needed, combining geophysical assessments with ecological data, long-term monitoring, and robust governance mechanisms to balance conservation with resource development.

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Comment -7 The part about future research directions in the conclusion section is slightly brief and could be further expanded.

Response 7 - We believe the expanded discussion above adequately addresses this point by incorporating (also in light of what suggested from the reviewer#2) both practical applications and implications for policy, which are now also reflected in the revised conclusion

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The submitted manuscript presents an engaging exploration of its subject matter; however, there are several areas that would benefit from refinement to enhance the clarity, precision, and overall depth of the presentation. In particular, the expression of key concepts and the accuracy of technical descriptions should be further developed. To support the authors in improving their work, I have highlighted a number of critical aspects that require attention. This feedback is intended to assist in making the manuscript more coherent, accessible, and effective in conveying its scientific contribution. For greater clarity and ease of application, my detailed observations and recommendations have been provided in the annotated PDF. I am confident that implementing these suggestions will substantially strengthen the manuscript and align it more closely with the publication standards of the journal.

 

 

1 - I recommend that the authors consider selecting a more engaging and strategically crafted title for their manuscript, one that not only captures the reader's attention but also subtly conveys the broader implications of their research. A stronger title can enhance the visibility and impact of the work, attract a wider readership, and better position the study within the relevant scholarly discourse.

 

 

2 - I suggest that the authors consider making the description of the featured applications more concise. Streamlining this section could enhance the overall clarity and focus of the manuscript, making it easier for readers to quickly grasp the key contributions without being overwhelmed by excessive detail.

 

 

3 - I recommend that the authors revise the abstract to place greater emphasis on the applications and broader implications of their research. Highlighting these aspects more clearly would help convey the significance and potential impact of the study from the outset, thereby making the manuscript more appealing and accessible to a wider audience.

 

 

4 - I suggest that the authors add a few more keywords to their manuscript, as keywords play a crucial role in indexing and making papers more easily discoverable through major search engines and academic databases. Expanding the keyword list could significantly enhance the visibility and reach of their work.

 

 

5 - While the introduction effectively outlines the key environmental concerns and economic interests associated with deep-sea mining, it could benefit from a more structured and focused narrative. In particular, the section tends to repeat some concepts (e.g., environmental risks and knowledge gaps) and mixes scientific observations with general statements without clearly separating evidence-based findings from broader commentary. A more concise and logically organized presentation would improve clarity and scientific rigor, making the manuscript stronger and more impactful for the reader.

 

 

6 - in the introduction section, from row 33 to row 36, where authors state "[...] However, the process of deep-sea mining is not without challenges and risks. Environmental concerns and potential damage to fragile ecosystems have raised questions about the sustainability of this industry. [...]" this important statement lacks citations that properly contextualize it within the framework of the international scientific literature. Consequently, the authors should cite  here the following work, which explicitly addresses the environmental impacts of activities resulting from geophysical prospecting:

-Tomassi, A., de Franco, R. and Trippetta, F., 2025. High-resolution synthetic seismic modelling: elucidating facies heterogeneity in carbonate ramp systems. Petroleum Geoscience, 31(1), pp.petgeo2024-047.

 

 

7 - I recommend enlarging Figure 1, as it is currently difficult to fully appreciate its details. The authors might consider reorganizing the mosaic vertically, which could improve the readability and overall impact of the figure.

 

 

8 - I recommend enlarging Figure 2 as well, as it is currently difficult to fully appreciate all its elements. It might be more effective to place the image at the top and the table/list underneath, to enhance the overall clarity and facilitate a more intuitive reading of the figure.

 

 

9 - I greatly appreciated the paragraph on the geological setting, which is clear and well-structured. However, including a geodynamic sketch would make this section even more effective, providing readers with a visual summary that could enhance understanding of the described tectonic context.

 

 

10 - The "Results and Discussion" section provides a rich and detailed overview of hydrothermal activity and mineralization processes in back-arc environments, particularly in the SE Tyrrhenian Sea. However, the narrative occasionally leans toward a descriptive rather than an interpretative approach. A slightly stronger emphasis on the critical comparison between the different sites discussed — in terms of geological evolution, mineral potential, and environmental sensitivity — could further enhance the scientific depth and coherence of the discussion.

 

 

11 - I suggest that the conclusions, while effectively summarizing the work, could be further improved by placing stronger emphasis on the key findings and by clearly outlining the main take-home messages, explicitly linking them to the initial research questions. Additionally, the conclusions would benefit from a deeper discussion of the practical applications and broader implications of the study. Acknowledging the limitations of the current work and proposing directions for future research would also strengthen the overall impact of the manuscript, providing a more complete and compelling closure that highlights its contribution to the field and encourages continued investigation.

Comments for author File: Comments.pdf

Author Response

Reviewer #2

 

The submitted manuscript presents an engaging exploration of its subject matter; however, there are several areas that would benefit from refinement to enhance the clarity, precision, and overall depth of the presentation. In particular, the expression of key concepts and the accuracy of technical descriptions should be further developed. To support the authors in improving their work, I have highlighted a number of critical aspects that require attention. This feedback is intended to assist in making the manuscript more coherent, accessible, and effective in conveying its scientific contribution. For greater clarity and ease of application, my detailed observations and recommendations have been provided in the annotated PDF. I am confident that implementing these suggestions will substantially strengthen the manuscript and align it more closely with the publication standards of the journal.

We sincerely thank Reviewer #2 for their thorough evaluation and constructive comments. Their valuable feedback has greatly contributed to improving the clarity, rigor, and overall quality of our manuscript. All corrections were made also taking into account the comments of the reviewer #1.

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Comments 1 - I recommend that the authors consider selecting a more engaging and strategically crafted title for their manuscript, one that not only captures the reader's attention but also subtly conveys the broader implications of their research. A stronger title can enhance the visibility and impact of the work, attract a wider readership, and better position the study within the relevant scholarly discourse.

Response 1 – Agree. The original title:

Hydrothermal vents in the SE Tyrrhenian Sea: multi-proxy geophysical support for (potential?) deep sea mining activities

Was revised to

Volcanic Rejuvenation and Hydrothermal Systems: Implications for Conservation and Resource Assessment in the South-eastern Tyrrhenian Sea

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Comments 2 - I suggest that the authors consider making the description of the featured applications more concise. Streamlining this section could enhance the overall clarity and focus of the manuscript, making it easier for readers to quickly grasp the key contributions without being overwhelmed by excessive detail.

Response 2 – Agree.

The Original text “We present a state-of-the-art overview of potential seafloor areas in the southeastern Tyrrhenian Sea...”

Was revised to:

We provide a concise overview of prospective seafloor sites in the southeastern Tyrrhenian Sea with potential for future deep-sea mining, within the context of the Italian Exclusive Economic Zone and newly established Ecological Protection Zones.

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Comments  3 - I recommend that the authors revise the abstract to place greater emphasis on the applications and broader implications of their research. Highlighting these aspects more clearly would help convey the significance and potential impact of the study from the outset, thereby making the manuscript more appealing and accessible to a wider audience.

Response 3 – Agree. The abstract was revised.

The southeastern Tyrrhenian Sea is a back-arc basin characterized by the onset of vol-canism over the past ~11 million years and the development of numerous volcanic sea-mounts. Hydrothermal venting is predominantly concentrated in the southeastern sector, encompassing the Aeolian volcanic arc and major volcanic edifices such as Palinuro and Marsili. These systems frequently exhibit zones of localized magnetic depletion (demag-netization) within otherwise magnetized volcanic structures, often linked to hydrother-mal alteration. Notably, volcanic rejuvenation phases are commonly associated with ac-tive hydrothermal circulation. In response to mounting ecological concerns, the Italian government has delineated extensive Ecological Protection Zones (EPZs), including those in the eastern Tyrrhenian sector. These EPZs encompass a series of prominent sea-mounts—Palinuro, Marsili, Vercelli, Vavilov, Magnaghi, Enarete, and Anchise—that ex-hibit morphological evidence of rejuvenation and magnetic anomalies consistent with hydrothermal modification. Such features are indicative of potentially mineralized sys-tems, relevant for future resource exploration. A comprehensive evaluation of both the ecological significance and the mineral potential of these areas is now imperative. Bal-ancing environmental conservation with the strategic assessment of deep-sea mining prospects will be essential to mitigate biodiversity loss while promoting the sustainable use of marine mineral resources.

------

Comments 4  - I suggest that the authors add a few more keywords to their manuscript, as keywords play a crucial role in indexing and making papers more easily discoverable through major search engines and academic databases. Expanding the keyword list could significantly enhance the visibility and reach of their work.

Response 4: - Agree. We added We added: “Volcanic rejuvenation” and “Demagnetization” as new keywords

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Comments 5 - While the introduction effectively outlines the key environmental concerns and economic interests associated with deep-sea mining, it could benefit from a more structured and focused narrative. In particular, the section tends to repeat some concepts (e.g., environmental risks and knowledge gaps) and mixes scientific observations with general statements without clearly separating evidence-based findings from broader commentary. A more concise and logically organized presentation would improve clarity and scientific rigor, making the manuscript stronger and more impactful for the reader.

Response  5 - We revised the introduction to improve its logical structure, removed redundancies, and clarified distinctions between scientific findings and broader commentary. The section now more effectively supports the rationale for this case study

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Comments 6 - in the introduction section, from row 33 to row 36, where authors state "[...] However, the process of deep-sea mining is not without challenges and risks. Environmental concerns and potential damage to fragile ecosystems have raised questions about the sustainability of this industry. [...]" this important statement lacks citations that properly contextualize it within the framework of the international scientific literature. Consequently, the authors should cite here the following work, which explicitly addresses the environmental impacts of activities resulting from geophysical prospecting:

-Tomassi, A., de Franco, R. and Trippetta, F., 2025. High-resolution synthetic seismic modelling: elucidating facies heterogeneity in carbonate ramp systems. Petroleum Geoscience, 31(1), pp.petgeo2024-047.

Answer 6 - We added the suggested citation in the discussion section:

To address these gaps, future research should focus on: 1) high-resolution geophysical and geochemical surveys at priority sites to better constrain the nature and extent of subsurface mineralization, also including advanced facies recognition with reflection seismic profiles acquired with deep-towed systems and specifically processed, that could be really promising to properly understand the real dimensions of DSM facies [e.g., Tomassi et al., 2025]; and 2) in situ biological and ecological studies to assess vulnerability; and species endemism in hydrothermal vent communities and integrated impact assessments that model the cumulative effects of potential DSM operations within sensitive volcanic and hydrothermal ecosystems.

Reference added:

Tomassi, A., de Franco, R., & Trippetta, F., 2025. High-resolution synthetic seismic modelling: elucidating facies heterogeneity in carbonate ramp systems. Petroleum Geoscience, 31(1), pp. petgeo2024-047

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Comment 7 - I recommend enlarging Figure 1, as it is currently difficult to fully appreciate its details. The authors might consider reorganizing the mosaic vertically, which could improve the readability and overall impact of the figure.

Response 7 – We have tried, but the results are really awful….

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Comments 8 - I recommend enlarging Figure 2 as well, as it is currently difficult to fully appreciate all its elements. It might be more effective to place the image at the top and the table/list underneath, to enhance the overall clarity and facilitate a more intuitive reading of the figure.

Response 8 - Agree. The Fig. 2 was changed as suggested

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Comments 9 - I greatly appreciated the paragraph on the geological setting, which is clear and well-structured. However, including a geodynamic sketch would make this section even more effective, providing readers with a visual summary that could enhance understanding of the described tectonic context.

Response 9 – A geodynamic sketch is included in the Fig. 1A

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Comments 10 - The "Results and Discussion" section provides a rich and detailed overview of hydrothermal activity and mineralization processes in back-arc environments, particularly in the SE Tyrrhenian Sea. However, the narrative occasionally leans toward a descriptive rather than an interpretative approach. A slightly stronger emphasis on the critical comparison between the different sites discussed — in terms of geological evolution, mineral potential, and environmental sensitivity — could further enhance the scientific depth and coherence of the discussion.

Response 10 – Agree. We revised the "Results and Discussion" section to better highlight comparative interpretations among the seamounts in terms of geological evolution, mineralization potential, and conservation relevance.

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Comments 11 - I suggest that the conclusions, while effectively summarizing the work, could be further improved by placing stronger emphasis on the key findings and by clearly outlining the main take-home messages, explicitly linking them to the initial research questions. Additionally, the conclusions would benefit from a deeper discussion of the practical applications and broader implications of the study. Acknowledging the limitations of the current work and proposing directions for future research would also strengthen the overall impact of the manuscript, providing a more complete and compelling closure that highlights its contribution to the field and encourages continued investigation.

Response 11 - The conclusions were revised to clearly state the key findings, link them back to the original research questions, acknowledge limitations, and propose directions for future research, thereby enhancing the manuscript’s impact and closure.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised version by the author has addressed the concerns, and I recommend acceptance.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

 

I am pleased to inform you that I have completed my review of the revised manuscript. It is evident that the changes made in response to the reviewers' comments have significantly enhanced the clarity and depth of your paper. The efforts you have put into addressing the concerns and suggestions have not only improved the manuscript but have also augmented its contribution to the field.

 

In light of the substantial improvements made, I believe that the manuscript is now well-prepared for publication. The revisions have effectively strengthened the arguments, enriched the data presentation, and refined the overall narrative, thereby solidifying its scholarly value.

 

Thank you for your diligence and commitment to enhancing your work. I look forward to seeing your research published and contributing to ongoing discussions in your area of expertise.

 

Best regards