Review Reports

Round 1

Reviewer 1 Report

Wind speed and direction are a much neglected factor in trying to understand phytoplankton blooms and succession (as in this case diatoms vs coccolithophorids in the Black Sea). I support publication of this work. The graphs in Figs 3 and 6 are nicely done. The English grammar needs to be significantly improved, and I attach a marked up manuscript. My only other comment is also to take note of some criticisms of Sverdrup's hypothesis, eg. Michael J Behrenfeld 2010. Abandoning Sverdrup's critical depth hypothesis on phytoplankton blooms. Ecology 91(4):977-89. doi: 10.1890/09-1207.1.. 

Comments for author File: Comments.pdf

Author Response

SUMMARY RESPONSE: The authors thank the reviewer for a thorough and detailed analysis of the manuscript.

COMMENTS: The English grammar needs to be significantly improved, and I attach a marked up manuscript.

RESPONSE: All comments have been taken into account and appropriate corrections have been made in the text.

COMMENTS: My only other comment is also to take note of some criticisms of Sverdrup's hypothesis, eg. Michael J Behrenfeld 2010. Abandoning Sverdrup's critical depth hypothesis on phytoplankton blooms. Ecology 91(4):977-89. doi: 10.1890/09-1207.1..

RESPONSE: Changed

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper analyzes the composition, abundance and biomass of the Black Sea phytoplankton community as a function of wind strength and water column stability. The results are a valuable contribution to the knowledge of the spatial and temporal distribution of phytoplankton in this area, and the commonly known hypotheses were additionally tested. Given the absence of species of the genus Chaetoceros, which were otherwise prevalent in the community, it would be interesting to see the concentration of nutrients, if this is possible.

In the results section, data from the literature should not be used but should be included in the discussion. e.g. in section 3.2 chl dynamics in the open waters line 189-194.

Author Response

SUMMARY RESPONSE: We thank the reviewer for a detailed analysis of the manuscript.

COMMENTS: Given the absence of species of the genus Chaetoceros, which were otherwise prevalent in the community, it would be interesting to see the concentration of nutrients, if this is possible.

RESPONSE: A detailed analysis of the effect of nutrition on phytoplankton can be found in the article: Silkin, V.A.; Pautova, L.A.; Giordano, M.; Chasovnikov, V.K.; Vostokov, S.V.; Podymov, O.I.; Pakhomova, S.V.; Moskalenko, L.V. Drivers of phytoplankton blooms in the northeastern Black Sea. Mar. Poll. Bull. 2019, 138, 274-284. It shows that high concentrations of nitrogen are necessary for the growth of diatoms of the genus Chaetoceros.

COMMENTS: In the results section, data from the literature should not be used but should be included in the discussion. e.g. in section 3.2 chl dynamics in the open waters line 189-194.

RESPONSE: Changed

Author Response File: Author Response.pdf