High-resolution analysis of a North Sea phytoplankton community structure based on in situ flow cytometry observations and potential implication for remote sensing

Thyssen, M.; Alvain, S.; Lefèbvre, A.; Dessailly, D.; Rijkeboer, M.; Guiselin, N.; Creach, V.; Artigas, L.-F.

doi:https://doi.org/10.5194/bg-12-4051-2015

Articles | Volume 12, issue 13

https://doi.org/10.5194/bg-12-4051-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/bg-12-4051-2015

© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 12, issue 13

Research article

|

07 Jul 2015

Research article |

| 07 Jul 2015

High-resolution analysis of a North Sea phytoplankton community structure based on in situ flow cytometry observations and potential implication for remote sensing

M. Thyssen, S. Alvain, A. Lefèbvre, D. Dessailly, M. Rijkeboer, N. Guiselin, V. Creach, and L.-F. Artigas

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Final revised paper (published on 07 Jul 2015)
Preprint (discussion started on 07 Nov 2014)

Interactive discussion

Status: closed

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

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- Supplement

RC C7132: 'accepted subject to minor revisions', Anonymous Referee #1, 04 Dec 2014
- AC C9210: 'Reply to Reviewer 1', Melilotus Thyssen, 30 Mar 2015
RC C7164: 'Authors need to discuss the findings in a broader context', Anonymous Referee #2, 05 Dec 2014
- AC C9215: 'Reply to Reviewer 2', Melilotus Thyssen, 30 Mar 2015
RC C7224: 'Review - Phytoplankton community structure in the North Sea', Anonymous Referee #3, 09 Dec 2014
- AC C9218: 'Reply to Reviewer 3', Melilotus Thyssen, 30 Mar 2015
AC C9208: 'General comment from the authors', Melilotus Thyssen, 30 Mar 2015

Peer-review completion

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

AR by Melilotus Thyssen on behalf of the Authors (30 Mar 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (06 Apr 2015) by Emmanuel Boss

RR by Anonymous Referee #2 (08 Apr 2015)

RR by Anonymous Referee #3 (13 Apr 2015)

Suggestions for revision or reasons for rejection

This is my second review of the manuscript by Thyssen et al. The manuscript has been slightly improved while the answers to my review have been somewhat disappointing, for 2 reasons.

First, it appears that the authors have for some reasons not worked on many of my secondary comments, going from the main comments to those associated with page 15639 (almost the end of the first draft), skipping all the material in between. I have made the effort to repeat all these comments with updated line numbers. Most deal with wording and minor clarifications (see below).

Second, some of my main comments seem to have been interpreted as a request to add a lot more about the PHYSAT approach or about flow cytometry, which is a misunderstanding. I fully understand that the authors do not want to enter into details on these topics; this is indeed not needed, nor requested. My comments suggested the possibility of adding just a little bit of text to ease the understanding of the manuscript by non-experts. I still think that defining Ra with its equation would help non-experts in optics to grasp what PHYSAT is about, that splitting the almost monolithic Section 2.1 into paragraphs with a couple of introductory sentences here or there would help non-experts in cytometry. I as well think that recalling in the discussion that non-phytoplankton material (e.g., sediments) can contribute to the differences in optical properties observed between clusters is appropriate, and that showing nLw spectra (and not only the anomalies) is interesting. Again, these points do not imply anything about PHYSAT’s developments. Same thing for my comment on Figure 12 (it was just about colors… but I have bad eyesight).

Ultimately, while I’m leaving the decision to the authors, I would encourage them to consider taking these comments into account, in order to make the manuscript more readable and complete. I’d also recommend to act on the secondary comments below.

Abstract
l.30: “spatial”
l.44: “chlorophyll-a” (or ‘a’ in italic).
l.47: I’d remove “classical”
l.48: “and remote sensing”

Introduction
l.69: “such a proxy”
l.70: “does not”
l.78: define DMSP at first use
l.79: the last properties, thug relevant for the biogeochemical cycles are not directly linked to the elemental cycles.
l.91: I’d suggest: “algorithms applied to remote sensing data”.
l.107: I’d start a new paragraph after “available”.
l.111: “It is critical to understanding…” I’d say.
l.126-127: “in situ data describing phytoplankton …”
l.128: “with a totally”
l.137: “significantly distinct” ?
l.138: “the case in/with”

Section 2.1
The use of several paragraphs would help in making the description of methods clearer.

l.160: “1-10 cm3 of seawater”
l.171: the acronym PMT may defined here (it is used afterwards).
l.172: are the 2 trigger levels associated with the 2 photomultipliers?
l.174: “less concentrated”
l.195: “above this value” ? I think I understand the sentence but it is not well written.
l.199: “pre-determined”: not clear what this means at this stage.

Section 2.2
l.204: “ship’s seawater” ?
l.212: MODIS on-board Aqua I guess
l.225: please correct this sentence. Are the data Level-2 or Level-3? (the latter if they are 4-km data).
l.233: MLD is not a temperature difference… I’d suggest: “defined as the depth associated with an observed temperature difference of more than 0.2C with respect to the surface…”

Section 2.5
l.237: “remotely sensed”
l.241: “aerosol optical thickness” I guess
l.243-244: “coastal areas, that are not considered as open waters for remote sensing”: this sounds awkward; remote sensing (of ocean color) responds to optical properties.
l.255: “radiance”? “anomaly spectra”

Section 2.6
l.260: “normality was not applied”: is “applied” really the proper word here?
l.264: “remotely”

Section 3.1
l.277: “four … zones” ?
l.278: “associated with”
l.279: “samples varying between...” ? (the sentence is currently incorrect).
l.290: “3 E” ?

Section 3.2
l.297: repeating “cluster” each time may not be necessary
l.301: “within the Micro2 cluster”: what about the other clusters? Is it related to size?
l.303-304: “25 pictures collected within 47 counted cells”: what does it mean exactly? Is it random or related to a choice or size?

Section 3.4
l.359: “remotely”
l.363-365: this further selection is not clear to me.
l.393: “associated with”
l.395: synthesis”: do the authors mean ‘composite’?
l.397: “tongue”?

Section 4
l.404: “spatial”
l.413: “SFC” ?
l.427: “which is needed”
l.432: “taxonomic”
l.433: the use of “although” is incorrect here.
l.446: “possibly related” ? “taxonomic”
l.465: “inter-bloom”: please specify what that refers to.
l.470: “… fell when…”: considering what’s said before, this sounds contradictory.
l.476: “diffusing”? do the authors mean “scattering”?

Fig.3: I would specific in the legend that the colors are consistent across the different panels.

Fig.12: my comment here had nothing to do with PHYSAT. It is just a question of readability and contrast in colors….

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RR by Anonymous Referee #1 (15 Apr 2015)

ED: Reconsider after major revisions (22 Apr 2015) by Emmanuel Boss

AR by Melilotus Thyssen on behalf of the Authors (02 Jun 2015) Author's response Manuscript

ED: Publish as is (06 Jun 2015) by Emmanuel Boss

AR by Melilotus Thyssen on behalf of the Authors (09 Jun 2015)

Short summary

Phytoplankton community structure at a high spatial resolution (<3km) was studied in the North Sea during a cruise in May 2011. A first comparison with PHYSAT reflectance anomalies enables the extrapolation of the community structure rather than a dominant type at the North Sea scale and was interpreted with its hydrological characteristics. This will seriously improve our understanding of the influence of community structure on biogeochemical processes at the daily and basin scales.