Dear Dr. Feng,

Thank you very much for your point-by-point responses to the reviewers' comments. I appreciate that most of these are reasonable. So we would appreciate it very much if you could upload the latest version of your manuscript to the website of this journal. Once I get your paper, I will send it to the referee(s) again.

Thank you again for your wonderful effort to improve the manuscript.

Kind regards,

Koji Suzuki
Editor

Dear Authors,

We have received a review of your revised manuscript from an expert of the research field. So we would appreciate it very much if you could consider the points raised by the reviewer.

Thank you again for your nice effort to improve the manuscript.

Best regards,

Koji Suzuki
Editor

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Page 2, Line 5: What kind of ‘climate change’ are you talking about?

Page 4, Lines 5-6: “The marine coccolithophore Emiliania huxleyi (morphotype A, strain NIWA1108) was isolated from the Chatham Rise, east of New Zealand by Dr. H. Chang in 2009, as detailed in Feng et al. (2017).”
I have checked Feng et al. (2017) and Feng (2014) (PhD thesis of the corresponding author of this manuscript that shows original study of this manuscript), however, could not find detailed information of the strain in the papers. Please refer an appropriate paper that describes detailed information of the strain, or provide following information in this manuscript instead; sampling locality (latitude and longitude), sampling method, depth of seawater sample that yielded NIWA1108, hydrographic condition (temperature, salinity, etc.) of seawater at the sampling time, date of sampling, isolation method, and information of sampling cruise and cruise report. There is a possibility that culture strains originate from different hydrographic condition have different environmental preferences, as authors mention “we can speculate that the diverse E. huxleyi strains growing in different temperature regions might have different requirements for nitrogen ….” in the page 14. I think the detailed information of origin culture strain will help discussion of this study, and comparison of results from this study with result of other studies.

Page 4, Line 14; Please describe how did you know the culture strain is in exponential growth phase.

Page 5, Line 18: How long did you keep your subsample in dark 4˚C condition before counting?

Page 11, Line 15: Put ‘E. huxleyi’ in italics.

Page 13, Lines 14-16: “In our 15 accompanying study, the growth, photosynthetic, and calcification rates all increased with rising temperature until the optimal temperature was reached (Feng et al., 2017)”;
Please mention the optimal temperature of the strain NIWA 1108 reported by Feng et al. (2017), and then discuss whether the optimal temperature of the strain in laboratory experiment is same/close to the temperature of sampling locality.

Dear Dr. Feng,

It is a great pleasure now to accept your manuscript for publication in Biogeosciences. Thank you very much for responding to the comments from the last reviewer so carefully and completely.

Before it is published, please consider my editorial comments below.

P1, L19: nitrate and phosphate concentrations
P1, L20: partial pressure of CO2 (pCO2)
P3, L15–16: nutrient level
P3, L22: the magnitude of changes in each environmental driver
P5, L8: Add a space between ± and 0.
P11, L22: "E. huxleyi" should be italic.

Thank you again for choosing the EGU-journal Biogeosciences.

Sincerely,

Koji Suzuki
Editor