A stalagmite test of North Atlantic SST and Iberian hydroclimate linkages over the last two glacial cycles

Denniston, Rhawn F.; Houts, Amanda N.; Asmerom, Yemane; Wanamaker Jr., Alan D.; Haws, Jonathan A.; Polyak, Victor J.; Thatcher, Diana L.; Altan-Ochir, Setsen; Borowske, Alyssa C.; Breitenbach, Sebastian F. M.; Ummenhofer, Caroline C.; Regala, Frederico T.; Benedetti, Michael M.; Bicho, Nuno F.

doi:https://doi.org/10.5194/cp-14-1893-2018

Articles | Volume 14, issue 12

https://doi.org/10.5194/cp-14-1893-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/cp-14-1893-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 14, issue 12

Research article

|

11 Dec 2018

Research article |

| 11 Dec 2018

A stalagmite test of North Atlantic SST and Iberian hydroclimate linkages over the last two glacial cycles

Rhawn F. Denniston, Amanda N. Houts, Yemane Asmerom, Alan D. Wanamaker Jr., Jonathan A. Haws, Victor J. Polyak, Diana L. Thatcher, Setsen Altan-Ochir, Alyssa C. Borowske, Sebastian F. M. Breitenbach, Caroline C. Ummenhofer, Frederico T. Regala, Michael M. Benedetti, and Nuno F. Bicho

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Final revised paper (published on 11 Dec 2018)
Supplement to the final revised paper
Preprint (discussion started on 24 Nov 2017)
Supplement to the preprint

Interactive discussion

Status: closed

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

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RC1: 'Manuscript : A Stalagmite Test of North Atlantic SST and Iberian Hydroclimate Linkages over the Last Two Glacial Cycles Author(s): Rhawn F. Denniston et al. MS No.: cp-2017-146 MS Type: Research article', Anonymous Referee #1, 17 Dec 2017
- AC1: 'Response to Reviewer 1', Rhawn Denniston, 25 Jan 2018
RC2: 'Review of "Stalagmite Test of North Atlantic SST and Iberian Hydroclimate Linkages over the Last Two Glacial Cycles” by Rhawn F. Denniston et al.', Anonymous Referee #2, 18 Dec 2017
- AC2: 'Response to Reviewer 2', Rhawn Denniston, 25 Jan 2018
RC3: 'Review of Denniston et al Portugal stalagmite record', Anonymous Referee #3, 03 Jan 2018
- AC3: 'Response to Reviewer 3', Rhawn Denniston, 25 Jan 2018
RC4: 'Review of the manuscript “A Stalagmite Test of North Atlantic SST and Iberian Hydroclimate Linkages over the Last Two Glacial Cycles” by Denniston et al., submitted to Climate of the Past', Anonymous Referee #4, 11 Jan 2018
- AC4: 'Response to Reviewer 4', Rhawn Denniston, 25 Jan 2018
EC1: 'Editor comments', Nathalie Combourieu Nebout, 22 Jan 2018

Peer-review completion

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

ED: Reconsider after major revisions (30 Jan 2018) by Nathalie Combourieu Nebout

Dear authors,

I have read carefully your paper, the reviews and your responses to the four reviewers.
Both reviewers underlined that your data are very interesting and need to be published. I consider too that you provide a new speleothem dataset that represents a significant input for the scientific community. Nevertheless the form and structure of your paper is not yet appropriate at this stage for a publication. In fact, three of the reviewers recommend major revisions and I completely agree with their conclusions. So, at this step of the process and in view of the manuscript and discussion, I am obliged to conclude on a reconsideration of your paper after major revisions.

Please take into account very carefully what is proposed and recommended by reviewers 1, 2 and 4 (as well for the text as for the figures and tables to be modified or to be added). I will be very cautious about that. In any case, your revised version will entered in the review process again and surely resent to two of the first reviewers who asked to read again the paper after corrections.

Take attention to better explain what you do with your data and discuss more the results. Describe more the sites and the monitoring. Be more precise in your discussion. And I would like to have figures (old and new ones) that may clearly show what is explained in the text. As an example figure 6 has to be in accordance with its legend. The lettering used in the legend may be on the figure and/or the colours of the curves indicated in the legend.

Please send us the revised version quickly and do not forget to submit a document in track mode change in which it will be easy to see what has been changed in your manuscript. You can also join a supplementary explanation in an additional document.

Waiting after reading you revised manuscript.
With my best regards

Nathalie Combourieu-Nebout

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AR by Rhawn Denniston on behalf of the Authors (10 Jun 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (11 Jun 2018) by Nathalie Combourieu Nebout

RR by Anonymous Referee #1 (11 Jul 2018)

RR by Anonymous Referee #5 (17 Jul 2018)

ED: Reconsider after major revisions (30 Jul 2018) by Nathalie Combourieu Nebout

AR by Rhawn Denniston on behalf of the Authors (21 Sep 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (03 Oct 2018) by Nathalie Combourieu Nebout

RR by Anonymous Referee #5 (18 Oct 2018)

Suggestions for revision or reasons for rejection

Review of the revised manuscript titled:

“A Stalagmite Test of North Atlantic SST and Iberian Hydroclimate Linkages over the Last Two Glacial Cycles” (Denniston et al.)

My review is structured according to the major points that I listed in my first review.

1) The authors made some effort to show that recrystallization did not affect their isotope curve in a meaningfull way and show a comparison with isotope data off-axis in Fig. S7. However, I cite from my first review: “BG66 (the part dated at 219 kyr) show evidence of recrystallization at the growth axis”. I’m highlighting 219 ka, because this is the oldest part of the entire record and shows an important shift in both carbon and oxygen isotopes that matches a large shift in Portugese margin SST. Instead of replicating this shift, the authors chose a different part of the stalagmite to obtain a second isotope transect off-axis, where potential recrystallization is much less clear. I’m puzzled about the reasons for this, and emphasize the importance of replicating the record between 222.5 to 210 ka. Because this is where the recrystallization in this stalagmite is most obvious. So this still has to be addressed.

2) I acknowledge that the authors have improved the structure of the manuscript before the manuscript was sent out to me. I made several suggestions, that I think would improve it further. However, the authors have not adapted the structure of the manuscript. My opinion on this matter has not changed, so it is up to the editor to decide whether the structure of the manuscript is acceptable or not. In either case, these are my suggestions:

a. Line 272: This is the point where the structure of the manuscript becomes less clear to me. The section on “hendy tests” is not brought to a conclusion. Instead, the authors start discussing other controls on δ18O and δ13C. This can be VERY easily improved by starting chapter 4.3. by discussing the controls as in lines 273 to 311. And then discuss potential equilibrium / disequilibrium effects. Finishing with a small paragraph that the function of hendy-tests have been questioned. Stating that the signals visible in these stalagmites can be interpreted as a climate signal.

b. Another option would be to move the section on controls on d13C and d18O in section 4.3. to section 4.4. This way you can call section 4.3. “assessing equilibrium in speleothem δ18O and δ13C. I think this is the most elegant way to do it.
3) I cannot see the locations of the GNIP stations on the map, but in the author’s reply they mention that they do indicate it, so this might be an issue when uploading the manuscript? The addition of especially Portalegre is important, because it is located in the same climatic zone as the caves. The authors mention the correlations with air temperature at all GNIP stations, but not for precipitation amount. Please add this information for all GNIP stations.

Line 474: “model ages” I think you mean “age model uncertainties”

I think this manuscript should be accepted after the points mentioned above have been addressed.

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ED: Publish subject to minor revisions (review by editor) (22 Oct 2018) by Nathalie Combourieu Nebout

AR by Rhawn Denniston on behalf of the Authors (02 Nov 2018) Author's response Manuscript

ED: Publish subject to minor revisions (review by editor) (11 Nov 2018) by Nathalie Combourieu Nebout

Dear Authors,

I had a look on the new version of your manuscript and on the response to the last review.
Your paper has been considerably amended since the first version and you have taken into account most of the remarks of reviewers. The changes in the text were not easily visible as you have to send a version with the corrections in track mode changes. I would like to see exactly the changes made in the paper.
I have some last remarks on the presentation of your data in the figures:
1- Even if the different part of the speleothem are characterised by their ages, I think that indication of the names at the top of the graphs will be important for non-specialist readers especially on the first figure showing the record (Fig.9). In figure 10 the letters that are noted
2- in the caption do not appear on the schema and / or the colours of the curves are not indicated in the caption. Please choose one of the option. For my part I think that the letters (A to G) are requested on the draw.
3- In Figure 11, it will be of interest to have at the top indication of what is presented 13C record on the left and 180 record on the right to clarify what is represented; another option if to indicate that in the caption.
4- In the supplementary data :
a. In S1, what is represented exactly by the colours which colours corresponds to which stalagmite, reader needs more details. Ex: put the names of the different part of the stalagmite at the top of the figure. You say that 13C record is at the top of the figure and 180 record at the bottom, what I see is the opposite: 13C record at the bottom of the figure and 180record at the top. Same remarks for colours in S2. Put a short legend on the figure with colours and names of the core section.
b. In S4, the caption needs more details on what is exactly represented. Please indicate the names of the two stalagmites in correspondence with the colours
c. Please indicate what is represented by the circles and the red curve in S5.

These changes are very easy to do and thus I am waiting after the corrected version quickly and please if possible add a text with the amendments in track mode changes for a last checking.

With my best regards

Nathalie Combourieu-Nebout

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AR by Rhawn Denniston on behalf of the Authors (14 Nov 2018) Author's response Manuscript

ED: Publish subject to minor revisions (review by editor) (19 Nov 2018) by Nathalie Combourieu Nebout

AR by Rhawn Denniston on behalf of the Authors (26 Nov 2018) Author's response Manuscript

ED: Publish subject to technical corrections (27 Nov 2018) by Nathalie Combourieu Nebout

AR by Rhawn Denniston on behalf of the Authors (27 Nov 2018) Author's response Manuscript

Short summary

The sediment deposited off the coast of Portugal includes the remains of marine organisms and pollen washed to sea from Iberia. Analysis of both the pollen and the ocean sediments has revealed that the type and density of vegetation on land changed in concert with shifts in ocean temperature over centuries to tens of millennia. Proxies for climate in Portuguese stalagmites from the last two glacial periods show precipitation was reduced when sea surface temperatures fell.