Dear Authors
Thank-you again for your much-revised manuscript addressing the reviewer comments. I now have reports from the two referees who were willing to see it again; their comments are below.

I had a reviewer-type question of my own: whether the distinct signal at station 9 (only) on March 12-13 is consistent with the progress of the modelled surface tracer. This is not very clear in figure 10 where stations 7, 9, and 10 all seem to be on the edge of the tracer signal. I also had detailed Editor comments which appear below.

Now I apologise in case I did not send my comments directly to you previously as intended; I cannot now find the “sent” e-mail.

In any case, everything for you to attend to is now below: I am terming it “minor modifications” meaning that I will take a last look but I do not intend to send it back to referees.

Yours sincerely
John Huthnance


Referee #2
“I find that the paper has been substantially improved, and that the model simulation made a nice addition to the observations.

I suggest your re-write the abstract, just to summarize it all in a better way. The name of the ship is not essential information and does not belong in the abstract, but the name of the model should be there. The abstract should describe your findings. Here it is really only the 3 last lines that describe the findings.”

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Referee #3
“Comments on «Ventilation of the Northern Baltic Sea” by Thomas Neumann et al.
This paper presents strong indications that oxygen rich bottom water found in one profile collected in the Bothnian Bay, may have been formed by inflowing water from the Bothnian Sea mixed with surface water in the Northern Quark, and not by salt release from sea ice. I reviewed the first version of the manuscript, and is quite happy with the present revision. A few comments follows:
Page 3
Line 10: CDT should be CTD
Page 4
Figure text to Figure 4: … a CTD cast ‘was’ performed (not ‘were’)
Page 6
Line 32: is ‘fraction’ a better word than ‘share’?
Page 14
Should paragraph lines 12-13 perhaps be before paragraph lines 9-11?”

My detailed Editor comments
Page 1
Abstract last sentence. Better “Brine barely contributes to dense bottom water.”
Line 20. (Raateoja, 2013) is not now very “recent”.
Line 25. “a remarkable” -> “a significant” or “much”

Page 2
Lines 3-4. “on the way of the dense water plume” -> “on its way by the dense water plume.” or “en route by the dense water plume.”
Lines 15-16. “re-suspension” (spelling)
Line 17. “dense” (spelling)
Line 26. “allow for a” -> “allows”
Line 32. “. . consist . .”

Page 5
Line 4 Maybe “. . brine draining from the ice accumulated in the hole . .” ?


Page 11
Line 17. Maybe “. . solid lines indicate mixing of water masses . .”
Line 22 and figure 8 caption. -0.78 or -0.79?
Line 22. “.. constraints . .” (spelling)
Lines 26-27. Please relate “oxygen saturated” to the rest of the sentence.

Page 12
Line 3. “drops down” -> “decreases”
Line 5. “ago” -> “before”
Line 6. “leaving the surface water” -> “from the surface”?
Line 11. “. . sea-ice-covered . .”

Page 13, figure 10 caption. “. . next-to-bottom . .”. This is not quite clear. Do you mean the bottom model layer or the next one up?

Page 14 line 13. “descent” -> “descend”

Page 16
Line 5. “. . initiates . .”
Line 6. “. . shelves . .”
Line 11. “ . . Northern . .” Delete “a”
Line 16. “assume” -> “find”?
Line 25. “establishes” -> “is established”

Page 17 Figure A1 caption. “extent” (spelling)

Page 19 lines 1 and 5. “reasonably” (spelling)

Dear Authors
Thank-you for your re-revised manuscript. Please see the “Technical Corrections” below. After attending to these, please upload for final publication in Ocean Science (no more intervention by me). The manuscript will be copy-edited; please check that your intended meaning is kept.
Thank-you for publishing in Ocean Science.
Yours sincerely
John Huthnance

Technical corrections.
Page 1 Line 13. “Brine” – I think this needs explaining. Do you mean “Brine rejected during ice formation” (for example)?

Page 5
Line 1. “benthos” -> “benthic”?
Line 4. “with” -> “at”.

Page 6 Line 31. “two brine tracer for the passive tracer regions” maybe better as “a brine tracer for each passive tracer region”.

Page 10 bottom to Page 11 top. This sentence is better as “The density profiles suggest that the upper 20m to 30m are well mixed”

Page 11
Line 1. “. . starts just below . .”
Line 6. Better if “at all Bothnian Bay stations” starts the sentence.

Page 12 Figure 8 caption, sentence 4. Better “Only data . . . considered.”

Page 13 Figure 10 caption. “Bothnian” (spelling)

Page 14 Figure 11 caption. “Bothnian” (spelling)

Page 15
Line 9. “gives” -> “is”.
Lines 10-11 and figure 7d. Please check all the units of CDOM (should be mg l^-1 or g m^-3 ?)