A novel approach reveals high zooplankton standing stock deep in the sea

Vereshchaka, Alexander; Abyzova, Galina; Lunina, Anastasia; Musaeva, Eteri; Sutton, Tracey

doi:https://doi.org/10.5194/bg-13-6261-2016

Articles | Volume 13, issue 22

https://doi.org/10.5194/bg-13-6261-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/bg-13-6261-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 13, issue 22

Research article

|

21 Nov 2016

Research article |

| 21 Nov 2016

A novel approach reveals high zooplankton standing stock deep in the sea

Alexander Vereshchaka, Galina Abyzova, Anastasia Lunina, Eteri Musaeva, and Tracey Sutton

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Final revised paper (published on 21 Nov 2016)
Preprint (discussion started on 25 Apr 2016)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Comments on manuscript', A. Yamaguchi, 18 Jun 2016
RC2: 'Comments on A NOVEL APPROACH REVEALS HIGH ZOOPLANKTON STANDING STOCK DEEP IN THE SEA', Anonymous Referee #2, 28 Jul 2016
AC1: 'bg-2016-145', Alexander Vereshchaka, 17 Aug 2016

Peer-review completion

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

ED: Reconsider after major revisions (21 Aug 2016) by Gerhard Herndl

AR by Alexander Vereshchaka on behalf of the Authors (25 Aug 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (06 Sep 2016) by Gerhard Herndl

RR by Anonymous Referee #2 (07 Sep 2016)

Suggestions for revision or reasons for rejection

Dear authors,

I find that the manuscript has improved a lot. Thank you for following my comments and suggestions. Unfortunately, I still think that the manuscript needs some work, particularly regarding the statistics and figures. Please find my comments below.

Major comments:

Thank you for showing the scatter plots with the raw data. This is very useful in determining whether fitting a linear regression to your data is sensible. It looks like your data is significantly right-skewed: the majority of your data points are clustered near the origin and the trend you observe is driven by a few individual points. Please check whether your data is normally distributed before fitting a linear regression. A log-log transformation might help to fulfil the assumptions (i.e. normal distribution). You will likely still obtain a significant relationship between Chl and zooplankton abundance after transforming the data, but the results will be robust.

The notion of an inverted food pyramid is very interesting and it would be nice to have a graphical representation of this. Have you considered, maybe for a future study, to look at biomass spectra?

All figures need work. Many are lacking axis labels and legends. The font sizes are often too small. Many captions are incomplete. A point should be used to indicate decimal places (please also check the tables for this).

Minor comments:

Table 1: A table detailing the site of the locations and depth range has now been added. Why did you not include Chl concentrations, temperature? This would allow other scientists to build on your data.

L22: “I doing so”. Please change.

L25: Fish are not plankton, so I do not think you need to specifically mention them. Also, you exclude them from most of your data analyses.

L27: This sentence is a bit awkward as it mixes two ideas: vertical structure and trophic structure. I suggest rephrasing it to avoid confusion.

L28: You are not discussion biogeochemical cycles. Maybe better: “These findings, […], suggest that the importance of deep-ocean pelagic fauna for biogeochemical cycles maybe more important than previously thought”, or similar. Also, biogeochemical cycles are not mentioned anywhere else in the manuscript (except for in the abstract)!

L80: I would move this paragraph into the method section.

L98: “Samples have been taken following the same protocol”

L120: What is the upper size that is reliably caught with these nets? This should be mentioned as it especially important for the interpretation of the fish biomass.

L127ff: maybe nicer to say “dominated by…” rather than “mainly…”

L137: How did you obtain the length of an individual specimen?

L163: “decapod decapods”, please correct

L240: “quasi-exponential decrease”. Is this just based on eye-balling? Please clarify. A simple regression fit (i.e. biomass vs average depth) would make this statement more robust.

L243-245: This sentence is awkward and does not add much. Please rephrase or delete.

L256: It is interesting that you decided to average Chl over one year. Out of interest, have you tried correlations between biomass and Chl averaged over, for example, 6 months or 1 month prior to sampling? I suspect that the correlation would be a lot weaker (if any).

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ED: Reconsider after major revisions (10 Sep 2016) by Gerhard Herndl

AR by Alexander Vereshchaka on behalf of the Authors (16 Sep 2016) Author's response

ED: Publish as is (26 Sep 2016) by Gerhard Herndl

Short summary

Our primary finding of increased plankton biomass in the deep sea suggests that energy transfer efficiency from phytoplankton to intermediate and higher trophic levels has been underestimated, and that global carbon models need to account for the large portion of oceanic primary production that zooplankton is likely respiring in the deep-pelagic realm.