the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 19 Dec 2024
Marine heatwaves deeply alter marine food web structure and function
Abstract. Marine heatwaves (MHWs) are becoming longer, more frequent and more intense in recent decades. MHWs have caused large-scale ecological impacts, such as coral bleaching, mass mortality of seagrass, fishes and invertebrates, and shifts in abundance and distribution of marine species. However, the implications of these MHW-induced impacts on marine species for the structure and functioning of marine food webs are not clearly understood. In this study, we use the EcoTroph-Dyn ecosystem modelling approach to examine the impacts of MHWs occurring during the year's warmest month on the trophodynamics of marine ecosystems. EcoTroph-Dyn represents marine ecosystem dynamics at a spatial resolution of 1° longitude by 1° latitude and a temporal resolution of 14 days. We applied the model to simulate changes in trophodynamic processes, energy transfer and ecosystem biomass using daily temperature and monthly net primary production (NPP) that were derived from satellite observation from 1998 to 2021. We compared and contrasted the simulated changes in biomass by trophic levels with results generated from temperature and NPP time series that had been filtered to remove MHWs. Our results show a significant decline in biomass between 1998 and 2021 specifically caused by MHWs. For example, in the Northeast Pacific Ocean, our model simulated a specific MHW decline in biomass of 8.7 % ± 1.0 (standard error) in the region from 2013 to 2016. Overall, MHW-induced biomass declines are more pronounced in the northern hemisphere and Pacific Ocean. Moreover, the MHW-induced declines in high trophic level biomass were larger than lower trophic levels and lasted longer post-MHW. Finally, this study highlights the need to integrate MHWs into modelling the effects of climate change on marine ecosystems. It shows that the EcoTroph approach, and especially its new dynamic version, provides a framework to understand more comprehensively the implications of climate change for marine ecosystem structure and functioning.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(1761 KB)
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Supplement
(2483 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1761 KB) - Metadata XML
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Supplement
(2483 KB) - BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-3696', Anonymous Referee #1, 13 Feb 2025
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AC1: 'Reply on RC1', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
Publisher’s note: this comment is a copy of AC4 and its content was therefore removed on 19 March 2025.
Citation: https://doi.org/10.5194/egusphere-2024-3696-AC1 -
AC4: 'replaces and cancels previous "Reply on RC1"', Vianney GUIBOURD de LUZINAIS, 18 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3696/egusphere-2024-3696-AC4-supplement.pdf
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AC1: 'Reply on RC1', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
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RC2: 'Comment on egusphere-2024-3696', Anonymous Referee #2, 28 Feb 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3696/egusphere-2024-3696-RC2-supplement.pdf
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AC2: 'Reply on RC2', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
Publisher’s note: this comment is a copy of AC3 and its content was therefore removed on 19 March 2025.
Citation: https://doi.org/10.5194/egusphere-2024-3696-AC2 -
AC3: 'replaces and cancels previous "Reply on RC2"', Vianney GUIBOURD de LUZINAIS, 18 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3696/egusphere-2024-3696-AC3-supplement.pdf
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AC2: 'Reply on RC2', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-3696', Anonymous Referee #1, 13 Feb 2025
General comments
This article describes the application of an ecosystem dynamics model to a global sea temperature and NPP dataset to assess the occurrence of marine heatwaves and model the impacts of these heatwaves on ecosystems.
The article is concisely written and coherent overall, though there are minor grammatical errors throughout that should be amended to improve the readability and flow of the article. There are also a couple of errors with figure captioning and formatting. Some sections within the introduction and discussion could be further expanded, as described below.
I recommend minor revisions.
Specific comments
The abstract is effective.
The introduction section is quite short, and could be expanded with more examples and some deeper explanations, but provides a concise and generally effective overview of the topic. In general, it would be helpful to give more information about why MHWs have such sizable ecological consequences. For example, you could discuss why changes in temperature cause stress and how organisms respond to this (see DOI: 10.1126/science.1163156), as well as the fact that temperatures may be more likely to exceed critical thresholds during MHWs (see DOI: 10.1016/j.tree.2021.09.003).
The Material and Method and Results sections are generally well-written. See below for grammatical corrections.
The discussion is generally well-written and explains the findings and implications of this work with an appropriate level of detail. It would be interesting to include some recommendations for future development and use of the EcoTroph-Dyn model. For example, do you think the model could be used to predict the impacts of hypothetical future MHWs at global and local scales, and how much caution should be used when interpreting these findings?
Line 622 - do you have any ideas of why the model might have underestimated ecosystem responses to MHWs? Do you have any recommendations for how people using this model could account for this uncertainty?
Line 676 - Do you think it would be possible to design a species-specific or ecosystem-specific version of the EcoTroph-Dyn model that could more precisely predict the impacts of MHWs on specified regions or ecosystem types?
Line 681 - Dismiss any possibility of what?
The conclusion section is very short. It might be useful to include a brief summary of your findings regarding the accuracy of the EcoTroph-Dyn when model compared to real-world data from ‘the Blob’.
Technical and grammatical corrections
Line 11-12 - This sentence mixes present and past tense in a way that doesn’t completely make sense; “have become longer” might sound better.
Line 46 - Verb tenses are inconsistent; “are not ubiquitous and have varied largely” would sound more consistent. Additionally, it could be informative to provide more specific details about how ecological impacts have varied between different MHW events.
Line 69 - This sentence begins with “I used” while the rest of this paragraph uses “We” - it would be better to change this to “We used” for consistency.
Line 70 - There are two opening brackets in this sentence, but only one is needed. Also, MHWs rather than MHW.
Line 90 - “the total biomass of all consumers” is clearer than “whole consumers biomass”
Line 94-95 - The list of examples should be enclosed in brackets.
Line 118 - “each TL class”.
Line 130 - “represents” rather than “representing”
Line 222 - “MHWs last” or “MHW conditions last”
Line 225 - “is a hybrid model”
Line 267 - “large spatial variability was observed in NPP changes” is grammatically clearer
Line 403 - this line should use the ≥ (greater than or equal to) symbol
Line 426 - “the ‘without MHW’ scenario”
Line 430 - “the ‘with MHWs’ scenario”
Line 470 - “congruent with the findings of…” would be grammatically clearer
Line 471 - “ecosystem functions”
Line 473 - “ecosystem perturbations”
Line 476 - “the intensity and duration of MHWs have continuously increased”
Line 482-483 - “high TL biomass experienced greater impacts from MHWs, and was not able to recover to pre-perturbation levels as effectively as the low and medium TL biomass”
Line 585-587 - This sentence is unclear - I assume that what you mean is “the MHW was associated with a substantial increase in the abundance of pyrosomes limiting/stopping energy flow moving toward higher trophic levels (Gomes et al., 2024).”, but the grammatical structure of the sentence as written makes it somewhat difficult to follow.
Figures
Figure 3 - the caption needs to be more specific about what each panel represents.
For Figure 3a, the caption should specify how the spatial extent of MHWs was defined. Is this the percentage of the oceans’ total surface area that experienced a MHW during each year? Or the average spatial extent of each individual MHW event?
The figure keys state that Figure 3c depicts the average number of MHW days in each cell and Figure 3d depicts the average intensity of MHWs, but the figure caption states the opposite. It is also unclear whether Figure 3c depicts the average duration of each individual MHW event in days, or the total number of MHW days per year in each cell.
Figure 9 - the category labels on the X-axis are not vertically aligned with the violin plots.
Citation: https://doi.org/10.5194/egusphere-2024-3696-RC1 -
AC1: 'Reply on RC1', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
Publisher’s note: this comment is a copy of AC4 and its content was therefore removed on 19 March 2025.
Citation: https://doi.org/10.5194/egusphere-2024-3696-AC1 -
AC4: 'replaces and cancels previous "Reply on RC1"', Vianney GUIBOURD de LUZINAIS, 18 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3696/egusphere-2024-3696-AC4-supplement.pdf
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AC1: 'Reply on RC1', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
-
RC2: 'Comment on egusphere-2024-3696', Anonymous Referee #2, 28 Feb 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3696/egusphere-2024-3696-RC2-supplement.pdf
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AC2: 'Reply on RC2', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
Publisher’s note: this comment is a copy of AC3 and its content was therefore removed on 19 March 2025.
Citation: https://doi.org/10.5194/egusphere-2024-3696-AC2 -
AC3: 'replaces and cancels previous "Reply on RC2"', Vianney GUIBOURD de LUZINAIS, 18 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3696/egusphere-2024-3696-AC3-supplement.pdf
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AC2: 'Reply on RC2', Vianney GUIBOURD de LUZINAIS, 17 Mar 2025
Peer review completion
Post-review adjustments
Journal article(s) based on this preprint
Data sets
Species distribution estimated from four Species Distribution Models (SDM) database, with their trophic levels informations Vianney Guibourd de Luzinais https://doi.org/10.57745/PI0N92
Model code and software
EcoTroph-Dyn unexploited ecosystems Vianney Guibourd de Luzinais https://doi.org/10.57745/NHVPCR
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Vianney Guibourd de Luzinais
William W. L. Cheung
Didier Gascuel
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1761 KB) - Metadata XML
-
Supplement
(2483 KB) - BibTeX
- EndNote
- Final revised paper
General comments
This article describes the application of an ecosystem dynamics model to a global sea temperature and NPP dataset to assess the occurrence of marine heatwaves and model the impacts of these heatwaves on ecosystems.
The article is concisely written and coherent overall, though there are minor grammatical errors throughout that should be amended to improve the readability and flow of the article. There are also a couple of errors with figure captioning and formatting. Some sections within the introduction and discussion could be further expanded, as described below.
I recommend minor revisions.
Specific comments
The abstract is effective.
The introduction section is quite short, and could be expanded with more examples and some deeper explanations, but provides a concise and generally effective overview of the topic. In general, it would be helpful to give more information about why MHWs have such sizable ecological consequences. For example, you could discuss why changes in temperature cause stress and how organisms respond to this (see DOI: 10.1126/science.1163156), as well as the fact that temperatures may be more likely to exceed critical thresholds during MHWs (see DOI: 10.1016/j.tree.2021.09.003).
The Material and Method and Results sections are generally well-written. See below for grammatical corrections.
The discussion is generally well-written and explains the findings and implications of this work with an appropriate level of detail. It would be interesting to include some recommendations for future development and use of the EcoTroph-Dyn model. For example, do you think the model could be used to predict the impacts of hypothetical future MHWs at global and local scales, and how much caution should be used when interpreting these findings?
Line 622 - do you have any ideas of why the model might have underestimated ecosystem responses to MHWs? Do you have any recommendations for how people using this model could account for this uncertainty?
Line 676 - Do you think it would be possible to design a species-specific or ecosystem-specific version of the EcoTroph-Dyn model that could more precisely predict the impacts of MHWs on specified regions or ecosystem types?
Line 681 - Dismiss any possibility of what?
The conclusion section is very short. It might be useful to include a brief summary of your findings regarding the accuracy of the EcoTroph-Dyn when model compared to real-world data from ‘the Blob’.
Technical and grammatical corrections
Line 11-12 - This sentence mixes present and past tense in a way that doesn’t completely make sense; “have become longer” might sound better.
Line 46 - Verb tenses are inconsistent; “are not ubiquitous and have varied largely” would sound more consistent. Additionally, it could be informative to provide more specific details about how ecological impacts have varied between different MHW events.
Line 69 - This sentence begins with “I used” while the rest of this paragraph uses “We” - it would be better to change this to “We used” for consistency.
Line 70 - There are two opening brackets in this sentence, but only one is needed. Also, MHWs rather than MHW.
Line 90 - “the total biomass of all consumers” is clearer than “whole consumers biomass”
Line 94-95 - The list of examples should be enclosed in brackets.
Line 118 - “each TL class”.
Line 130 - “represents” rather than “representing”
Line 222 - “MHWs last” or “MHW conditions last”
Line 225 - “is a hybrid model”
Line 267 - “large spatial variability was observed in NPP changes” is grammatically clearer
Line 403 - this line should use the ≥ (greater than or equal to) symbol
Line 426 - “the ‘without MHW’ scenario”
Line 430 - “the ‘with MHWs’ scenario”
Line 470 - “congruent with the findings of…” would be grammatically clearer
Line 471 - “ecosystem functions”
Line 473 - “ecosystem perturbations”
Line 476 - “the intensity and duration of MHWs have continuously increased”
Line 482-483 - “high TL biomass experienced greater impacts from MHWs, and was not able to recover to pre-perturbation levels as effectively as the low and medium TL biomass”
Line 585-587 - This sentence is unclear - I assume that what you mean is “the MHW was associated with a substantial increase in the abundance of pyrosomes limiting/stopping energy flow moving toward higher trophic levels (Gomes et al., 2024).”, but the grammatical structure of the sentence as written makes it somewhat difficult to follow.
Figures
Figure 3 - the caption needs to be more specific about what each panel represents.
For Figure 3a, the caption should specify how the spatial extent of MHWs was defined. Is this the percentage of the oceans’ total surface area that experienced a MHW during each year? Or the average spatial extent of each individual MHW event?
The figure keys state that Figure 3c depicts the average number of MHW days in each cell and Figure 3d depicts the average intensity of MHWs, but the figure caption states the opposite. It is also unclear whether Figure 3c depicts the average duration of each individual MHW event in days, or the total number of MHW days per year in each cell.
Figure 9 - the category labels on the X-axis are not vertically aligned with the violin plots.