Dear Dr. Yang,

Thank you very much for considering the reviewers' comments. I consider that you generally responded to their comments well. So we would appreciate it very much if you could submit the latest version of your manuscript to us. Once we receive it, I will ask one of the referees to review it soon.

Again thank you for you nice efforts to improve your manuscript.

Kind regards,

Koji Suzuki
Editor

Dear Dr. Yang,

We have just received a review of your revised manuscript (see below). So we would be very grateful if you could consider the comments, and make a further revised paper with point-by-point responses.

Thank you again for your nice efforts to improve your paper.

Kind regards,

Koji Suzuki
Associate Editor

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As the authors agreed in their response that they have no direct evidence about causal relationship between 2013-2014 ANCP decrease and phytoplankton community composition change and low plankton biomass, I demand the authors to delete any mentions that suggests causal relationship between these matters.
They have clearly detected 2013-2014 ANCP decrease simultaneous change in phytoplankton community composition and plankton biomass, but this never means by themselves that the latter is the cause of the former. It is also possible that the former causes the latter, and it’s even more probable that the all of these findings is a results of single, not detected event (ca, GPP decrease).

Page 2, line 34
"it was most likely due to changes in plankton community composition"
=>this should be changed to like that:
“it was likely due to some biological processes rather than physical processes.”

Page15, lines 314-316.
"The sharp decrease……(Figure5a)." =>delete this sentence.

Page 17, lines 351-353.
“We suggest that the low phytoplankton biomass observed in the 2nd year ‘2013-14, Figure 5a), and the observed change in phytoplankton community composition (figure 5c) are the most likely causes for the ANCP decrease.”
=>should be changed to:
“We suggest that the change in GPP are the most likely causes for the ANCP decrease.”

Here you made big jump: Your elimination-method based discussion had suggested that GPP decrease must be required to explain observed ANCP decrease, but NONE in your discussion suggested that the cause of GPP decrease is reduced Chla abundance and change in plankton composition. Again, I say that these two events can be a RESULTS of GPP decrease as well as ANCP decrease, not the cause of it.

Page 17, lines 363-368
“These changes in phytoplankton community composition could be ultimately in response to…..”
=>should be changed to:
“Such change in GPP, as well as decreased Chla abundance and change in community composition could be ultimately in response to …..”

page 18, line 384-385
“the ANCP decrease was most likely due to changes in phytoplankton abundance and community composition after the “Blob” entered the area.
=>should be changed to such as:
“the ANCP decrease, as well as change in Chla abundance and phytoplankton composition, was most likely due to changes in GPP after the entry of the “Blob.” The ultimate cause of such GPP decrease, however, is not be able to specified by our analysis.”

Dear Dr. Yang,

It is a great pleasure now to accept your manuscript for publication in Biogeosciences. Thank you very much for responding to the last reviewer's comments carefully. Before it is published from the journal, please consider my technical corrections.

L55: Please add Peña et al. (2018) as a reference after Cavole et al. (2016).

L69 and hereafter: Please make sure to add a comma after "et al." in parentheses. For example, (Emerson et al., 2011).

L142 and L179: In Equations (1) and (2), is the unit of mol m-2 d-1 needed to indicate? Such units do not appear in another equations (e.g., Equations (6) and (7)). Probably the unit can be written in the main body of the text.

L365: high nutrient, low-chlorophyll region

Thank you very much again for choosing the EGU-journal Biogeosciences.

Kind regards,

Koji Suzuki
Associate Editor