Spatiotemporal variability of alkalinity in the Mediterranean Sea

Cossarini, G.; Lazzari, P.; Solidoro, C.

doi:https://doi.org/10.5194/bg-12-1647-2015

Articles | Volume 12, issue 6

https://doi.org/10.5194/bg-12-1647-2015

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

https://doi.org/10.5194/bg-12-1647-2015

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

Articles | Volume 12, issue 6

Research article

|

16 Mar 2015

Research article |

| 16 Mar 2015

Spatiotemporal variability of alkalinity in the Mediterranean Sea

G. Cossarini, P. Lazzari, and C. Solidoro

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Final revised paper (published on 16 Mar 2015)
Preprint (discussion started on 03 Sep 2014)

Interactive discussion

Status: closed

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

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RC C5455: 'Variability of alkalinity in the Mediterranean Sea', Anonymous Referee #1, 25 Sep 2014
AC C5656: 'a shot comment to review#1 comments', Gianpiero Cossarini, 02 Oct 2014
RC C5695: 'Review of „Space-time variability of alkalinity in the Mediterranean Sea“ by G. Cossarini, P. Lazzari, and C. Solidoro, manuscript submitted for publication in Ocean Science.', Anonymous Referee #2, 06 Oct 2014
RC C6592: 'Review of bg-2014-400 Space-time variability of alkalinity in the Mediterranean Sea', George Triantafyllou, 10 Nov 2014

Peer-review completion

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

AR by Gianpiero Cossarini on behalf of the Authors (28 Jan 2015) Author's response Manuscript

ED: Reconsider after major revisions (29 Jan 2015) by Aldo Shemesh

ED: Referee Nomination & Report Request started (29 Jan 2015) by Aldo Shemesh

RR by Anonymous Referee #2 (05 Feb 2015)

Suggestions for revision or reasons for rejection

The authors have responded thoroughly and comprehensive to the comments by the reviewers. I do however have two comments; the first is more technical and should be easy to correct, the second one might need a little more work.
Table 3 gives the regression coefficients for the TA/sal relation for the whole Med as annual average and for each season. However Figure 4 shows clearly that the S/TA relation is very different for different sub-basins. This is fine, but I find it difficult to decipher which of the relations in Figure 4 is for which area. Please either make a not in the plot, or add to table 3 (preferred). Maybe I misunderstand the table, and the regression is made without the Aegean and Adriatic data, which are both very different. Either way, more explanations to the table/figure are required.
Section 3.4: This section is new although this was discussed also in the original submission. Also figures 7 and 8 are new. I do have problems with the conclusions in section 3.4 regarding the biological effects on the variability of alkalinity (I should have noticed this in the first submission, but was alerted by the new figures, I guess). In the Mediterranean surface layer (i.e. the mixed layer) there is almost no nutrients present, so that rapid biological uptake of nutrients (i.e. of almost nothing) cannot really affect the alkalinity so much. This part of the results looks strange to me. Even more so since it is known that the Mediterranean Sea has a dominance of calcifiers, such as coccolitophores (e.g. Oviedo et al., 2015). Formation of calcite/aragonite shells would tend to reduce alkalinity of seawater, and when/if these shells sink out of the surface layer represent a sink of alkalinity. Is this considered in the model? Re-reading section 2.1. makes we wonder if calcium carbonate formation by phytoplankton is considered. Please confirm what is done. I would expect (from an educated guess) that the alkalinity flux due to calcium carbonate formation would vastly exceed that of inorganic nutrient utilization in the surface, but I might be wrong. I would like to see some discussion/explanation on this. Sorry that I did not notice first time around.

Oviedo, A., Ziveri, P., Álvarez, M., and Tanhua, T.: Is coccolithophore distribution in the Mediterranean Sea related to seawater carbonate chemistry?, Ocean Sci., 11, 13-32, 10.5194/os-11-13-2015, 2015.

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RR by Anonymous Referee #1 (13 Feb 2015)

ED: Publish subject to technical corrections (15 Feb 2015) by Aldo Shemesh

AR by Gianpiero Cossarini on behalf of the Authors (23 Feb 2015) Manuscript