A 2-decade (1988–2009) record of diatom fluxes in the  Mauritanian coastal upwelling: impact of low-frequency  forcing and a two-step shift in the species composition

Romero, Oscar E.; Ramondenc, Simon; Fischer, Gerhard

doi:https://doi.org/10.5194/bg-18-1873-2021

Articles | Volume 18, issue 5

https://doi.org/10.5194/bg-18-1873-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-18-1873-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 5

Research article

|

18 Mar 2021

Research article |

| 18 Mar 2021

A 2-decade (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: impact of low-frequency forcing and a two-step shift in the species composition

Oscar E. Romero, Simon Ramondenc, and Gerhard Fischer

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Final revised paper (published on 18 Mar 2021)
Preprint (discussion started on 13 Oct 2020)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Reviewer's comments', Anonymous Referee #1, 30 Oct 2020
- AC1: 'Reply to BGD Comments _ Rev 1', Oscar E. Romero, 14 Dec 2020
RC2: 'Review', Anonymous Referee #2, 16 Nov 2020
- AC2: 'Reply to BGD Comments _ Rev 2', Oscar E. Romero, 14 Dec 2020
AC3: 'Comment on bg-2020-336 revised version Feb 4th 2021', Oscar E. Romero, 04 Feb 2021

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (28 Dec 2020) by Ny Riavo G. Voarintsoa

AR by Oscar E. Romero on behalf of the Authors (19 Jan 2021) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Jan 2021) by Ny Riavo G. Voarintsoa

RR by Anonymous Referee #1 (27 Jan 2021)

RR by Anonymous Referee #2 (04 Feb 2021)

Suggestions for revision or reasons for rejection

From the reading of the new version of the paper one gets the impression that there wither was a mistake and the authors may have uploaded a version that is not their final version, or the reviews was done in a rush and not as carefully as it should. Not only there is a the mismatch between the new submitted version and the author’s response but also the English used in the added or rewritten parts of the manuscript, in particular in the discussion section does not fit the rest of the MS.

Aspects mentioned in the response has being accepted and to be revised but not done

RC2: What is the reason to use the term pelagial rather than pelagic? Although used for lakes I have not seen any paper that defends/justifies its use for the ocean environment.

AC: we will rephrase accordingly and use pelagic instead of pelagial throughout the MS.

The term is still used in the new version that was submitted.

RC2: The use of satellite images (composites for the n_ of years considered for each specific time interval / diatom phase) for comparison would also be important to verify the variability on the surface water and upwelling conditions.

AC: three pictures of chlorophyll a concentration have been added to Figure 1 (attached). They depict the average concentration of chlorophyll a for three winters (1997, 2002 and 2008), gained with SeaWIFs and MODIS (https://oceancolor.gsfc.nasa.gov/cgi/l3, details will be provided in the revised version of the MS). The high interannual variability is clearly recognized.

The figure 1 associated to the response letter does not correspond to the figure in the uploaded version, that is still the figure of version 1

RC2: Figure 4: Comparison of (a) clusters extracted from multivariate analysis with the environmental forcing variables (a1: Total diatom flux; a2: AMO; a3: Shannon diversity). Besides being too small and difficult to see, total diatom Flux and Diversity are not forcing variables. They all reflect the community adaptation to the regional conditions resulting from the forcing factor(s).

AC: we will rephrase this accordingly. NAO, AMO, ENSO and the diversity index C9 BGD Interactive comment Printer-friendly version Discussion paper Shannon-Weaver are indices while the total diatom flux is a variable. This was wrongly described in the original submission. The file resolution of Fig. 4 will be enlarged.

Not really done. The figure has the same exact size!

New Notes

352 - Based on outstanding shifts in the species-specific composition of the diatom assemblage occurred throughout the study interval (Fig. 2b). We propose three main intervals in the multiyear….

First sentence does not make sense. I believe the second sentence should follow without the full stop after Fig 2b.

395 - Fig. 4). The dominance of benthic taxa also prevails (after) afterward throughout until recently recovered traps at site CBmeso (Oscar E. Romero, unpublished data).

399 – 403 Paragraph needs rewriting

424 – 428 Paragraph needs rewriting

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ED: Publish subject to minor revisions (review by editor) (04 Feb 2021) by Ny Riavo G. Voarintsoa

AR by Anna Wenzel on behalf of the Authors (15 Feb 2021) Author's response

ED: Publish as is (16 Feb 2021) by Ny Riavo G. Voarintsoa

AR by Oscar E. Romero on behalf of the Authors (17 Feb 2021) Author's response Manuscript

Short summary

Upwelling intensity along NW Africa varies on the interannual to decadal timescale. Understanding its changes is key for the prediction of future changes of CO₂ sequestration in the northeastern Atlantic. Based on a multiyear (1988–2009) sediment trap experiment at the site CBmeso, fluxes and the species composition of the diatom assemblage are presented. Our data help in establishing the scientific basis for forecasting and modeling future states of this ecosystem and its decadal changes.