Dear authors,
Thank you for your responses to the reviewers' comments. Both experts have expressed major concerns about both the methods used in your study and some of your interpretations and conclusions, as well as the use of previous literature. I invite you to prepare a new manuscript, which should address and correct all these issues. The revised manuscript will be sent to both original reviewers and, if required, to new reviewers.
Thank you for submitting your work to Biogeosciences.
Best regards,
Emilio Marañón

Dear authors,

Thank you for your letter of response to the reviewers and for submitting a revised manuscript. The changes you have introduced solve some of the interpretation problems highlighted by the reviewers. While the information available is not sufficient to determine unequivocally the mechanism responsible for the lack of seasonality in integrated chla concentration, your comprehensive dataset is valuable and contributes to advance our understanding of the biological oceanography of subtropical pelagic ecosystems. I am therefore recommending publication of your manuscript in Biogeosciences, subject to minor revisions.

Please take into account the editorial comments below when preparing the final version of the article.

Thank you for submitting your work to Biogeosciences.

Best regards,

Emilio Marañón

Editorial comments***************************************

p. 2 line 3 Phrase ‘the GOM, as a whole, is a contrasted trophic environment’ is vague. What is a ‘trophic environment’? Please re-write; if what is meant is that, overall, the region is oligotrophic, just say so.

p.2 line 19: There are more recent studies highlighting the importance of changes in phytoplankton chlorophyll content: Behrenfeld et al. 2016 Nature Climate Change 6 323, Jakobsen and Markager (2016) Limnol. Oceanogr., 61: 1853–1868. Also the review by Halsey and Jones 2015 (Ann Rev Mar Sci) is relevant here. Note also that phytoplankton chla content changes not only in response to light, but is also sensitive to nutrient availability and temperature.

p.3 lines 4-5 What is measured here is fluorescence. Correct phrase is ‘chlorophyll fluorescence’, not ‘fluorescence chlorophyll’

page 3, lines 12. Here authors should state which are those mechanisms.

page 3 End of Introduction: remove ‘This is the most important result of our study’ (not informative).

page 4, lines 15-16. Confusing description of method. What is ‘above 0.9 times the mixed layer’? The MLD is a depth, say 50 m. Then 0.9 x 50 = 45 m. Would this mean that the value of CHL at 45 m is extrapolated to the surface? Please clarify, bearing in mind that ‘mixed layer’ is not the same as ‘mixed layer depth’.

page 4 line 29 ‘timeS’

********************************************************