On giant shoulders: how a seamount affects the microbial community composition of seawater and sponges

Busch, Kathrin; Hanz, Ulrike; Mienis, Furu; Mueller, Benjamin; Franke, Andre; Roberts, Emyr Martyn; Rapp, Hans Tore; Hentschel, Ute

doi:https://doi.org/10.5194/bg-17-3471-2020

Articles | Volume 17, issue 13

https://doi.org/10.5194/bg-17-3471-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-17-3471-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 13

Research article

| Highlight paper

|

08 Jul 2020

Research article | Highlight paper |

| 08 Jul 2020

On giant shoulders: how a seamount affects the microbial community composition of seawater and sponges

Kathrin Busch, Ulrike Hanz, Furu Mienis, Benjamin Mueller, Andre Franke, Emyr Martyn Roberts, Hans Tore Rapp, and Ute Hentschel

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Final revised paper (published on 08 Jul 2020)
Supplement to the final revised paper
Preprint (discussion started on 28 Jan 2020)
Supplement to the preprint

Interactive discussion

Status: closed

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

- Printer-friendly version

- Supplement

RC1: 'Review for "On giant shoulders: How a seamount affects the microbial community composition of seawater and sponges"', Anonymous Referee #1, 31 Jan 2020
- AC1: 'Response to Reviewer #1 (see attached PDF)', Ute Hentschel, 29 Mar 2020
RC2: 'Evaluation of Busch et al: On giant shoulders: How a seamount affects the microbial community composition of seawater and sponges.', Anonymous Referee #2, 16 Mar 2020
- AC2: 'Response to Reviewer #2 (see attached PDF)', Ute Hentschel, 29 Mar 2020

Peer-review completion

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

ED: Reconsider after major revisions (30 Mar 2020) by Tina Treude

AR by Ute Hentschel on behalf of the Authors (31 Mar 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (06 Apr 2020) by Tina Treude

RR by Anonymous Referee #2 (22 Apr 2020)

Suggestions for revision or reasons for rejection

Evaluation of Busch et al: On giant shoulders: How a seamount affects the microbial community composition of seawater and sponges (bg-2020-15-manuscript-version3).

The authors improved the manuscript considerably, and the new figures are a welcome addition that make the text better comprehensible. But still, there are a couple of issues left, and the authors' rebuttal to the original comments are not always convincing. Particularly, missing information regarding methodological aspects and a discussion which considers only part of the results make a further revision necessary. I will try to explain my concerns in detail below.

Detailed comments
(line numbers apply to the Response to Reviewer Comments in bg-2020-15-AC2-supplement.pdf).

L45: I am not sure about the policy of Biogeosciences, but I think this map is basic information that belongs into the paper proper, not into a supplement

L64: This is not sufficient. As a reviewer of the paper, but also as a reader I do not want (and usually do not have the time) to delve into any data repositories to search for information which is essential for the interpretation of the data, and I see no reason why the authors do not provide this information here.

L69: see comment above. And the information that seawater and sponges were sampled in close vicinity should be provided in the Methods section - this would be just one additional sentence.

L111 ff: I am still not happy with these extrapolations. It is far from clear which parameters go into this "machine-learning process". For example, how were (isolated) BW1 regions outside the data points discriminated from BW2 in the same area - just from depth, which is the only parameter available outside the sampling points? This extrapolation is particularly strange since only one BW1 data point exists, and a possible Taylor column which may be responsible for the BW1 cluster, is locally restricted. Currently, it is kind of a magic black box - something goes in (but the reader does not know what) and the predictions come out. Certainly it is not necessary to go into details, but some basic information of what's going on in the black box would be very useful. And the purpose of the extrapolations/predictions is still not clear: For the outcome of the study, they are not necessary, and they are in fact not used and interpreted in the paper.

L126: I fully agree that Fig. 3 provides a very good conceptual model of how the various parameters around Schulz Bank may interact. But I still feel that this figure does not belong into the results section, because it does not present results, which have not been shown before. In the text of the results section Fig. 3 is mentioned only in connection with the temperature profiles (which obviously are not own results and are hardly discernible in the figure), and that these determine the water mass distribution. Because the limits of the water masses are not indicated, even this information cannot be deduced from the figure.
Nethertheless, the figure is certainly useful for the interpretation of the results, and as such it is in fact used in the Discussion, where it should be placed.

L150: This has to be clarified. According to M&M, 19 stations were sampled, and exactly these 19 stations show up as dots in Fig. 2B, one of which is labelled BW1. Have there multiple (independent) microbial samples been taken per station? This is not mentioned in M&M, but is important information.

L163: I am sorry if the authors feel that my comment criticises their sampling design. I am fully aware of the limitations of deep-sea sampling, and I acknowledge that the authors collected an impressive dataset. My comment aimed at the incomplete information provided in the text - one example is shown in the comment above.

L204: Again, I do not deny the value of the study, on the contrary. But, just looking at the data, some patterns are quite striking, and even if they cannot be tested statistically, they may be relevant and should be considered, e.g. the relative abundances in BW1 being very different from the other clusters.

L214 (and elsewhere in the text and figures): the F value in ANOVA is a ratio, and hence the dF comprise two values.

L240: It is fully ok to discuss the presented data, but since the stations are not directly comparable due to the different distances between near-bottom and water column samples, some cautious statement about the limitations of the conclusion would be appropriate

L244: I do not know where this knowledge comes from, but it is simply wrong. Given the same driving forces, anticyclonic Taylor caps/columns are generated also at seamounts in the southern hemisphere, but of course in counter-clockwise direction (anticyclonic = clockwise in northern hemisphere, counter-clockwise in southern hemisphere). Examples can be found, for instance, in Rogers et al. 2017, Pelagic communities of the South West Indian Ocean seamounts: R/V Dr Fridtjof Nansen Cruise 2009-410, DSR II Vol. 136

L293: I cannot follow this argumentation ("… would enormously inflate the discussion"), and I find it strange to leave the interpretation of results to the reader. If results of the other clades and sponges do not add to the discussion or are not relevant, they can be omitted. The authors now state that Chloroflexi in G. hentscheli are discussed as "representative example". For what is this example representative? Does it mean that the results are similar in the other phyla and clades? Then this has to be stated. But looking at the results, this is certainly not the case.

L324: see also my comment to L64 - the sampling design in relation to the three cruises is not comprehensible from the information given in the paper, and searching in Pangaea is not a reasonable option. And I still miss some convincing statement why interannual variability is no issue.

L330: This is exactly the point. If an influence (of biogeochemical factors) is suggested, the underlying assumption is a causal relationship, which my comment pointed at.

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ED: Reconsider after major revisions (22 Apr 2020) by Tina Treude

Dear Katrin and Co-Workers,

after the review of the revised manuscript, the reviewer has still some comments and requests that warrant a second major revision. However, my understanding is that the required modifications are mostly of technical nature and you should be able to implement them easily. The reviewer is generally very supportive of the study and has a high appreciation of the dataset. I advice you to take the suggestions seriously.

I have a few comments myself in response to the reviewer's suggestion:

- I agree that Fig S1 (map) should be included in the main manuscript. I am a little irritated, however, that instead of a single red dot marking the location of the study site there appear to be an accumulation of dots. Do these mark different locations? If so, please add a zoomed-in insert map to the main map that provides enough resolution to tell the dots apart. If not, then please reduce to just one dot.

- The reviewer finds that referencing the interactive map provided on PANGAEA is not sufficient and requests to incorporate more details into the actual manuscript. I sympathize with this request. I advice you to extract the minimum amount of information required from PANGAEA to understand the study and provide it in the manuscript. This does not have to be the entire map, just as much information that is required to follow and understand your study. Basically, someone should not be required to go to PANGAEA to follow your study. Data repositories along publications are mainly meant to provide details not required for your interpretations and to allow others to make use of the data in the future.

- The reviewer suggest to move Figure 3 to the discussion, because no new (unpublished) data are presented. If that is the case, I agree with with this suggestion. If, however, new data were incorporated, I would be OK with leaving it in the results but please provide more details of the combination of new and existing datasets that went into the plot.

Let me know in case you have any questions.

Please provide a point-by-point response and a track-changes-version of your manuscript when you submit the revised manuscript.

All the best and stay safe!
Tina

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AR by Ute Hentschel on behalf of the Authors (29 Apr 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (11 May 2020) by Tina Treude

RR by Anonymous Referee #2 (27 May 2020)

ED: Publish as is (28 May 2020) by Tina Treude

AR by Ute Hentschel on behalf of the Authors (29 May 2020) Manuscript

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Short summary

Seamounts are globally abundant submarine structures that offer great potential to study the impacts and interactions of environmental gradients at a single geographic location. In an exemplary way, we describe potential mechanisms by which a seamount can affect the structure of pelagic and benthic (sponge-)associated microbial communities. We conclude that the geology, physical oceanography, biogeochemistry, and microbiology of seamounts are even more closely linked than currently appreciated.