Dear Patrick,

Thank you for your response to the review comments. I would like to invite you to submit a final revised manuscript that includes the revisions referred to in your response, and that addresses all of the review comments.

In preparing your revised manuscript, I would request that you please highlight the changes that have been made. I would also suggest that you consider the following additional points:

1. Given the emphasis on ‘monospecificity’ in this study, I think it is important that your figures illustrating the new benthic foraminiferal radiocarbon data (Fig. 5 and 6) show four curves in each instance (one for each species ‘category’ shown in Figure 5). Indeed, I think that Figure 5E would also be more informative if the different records from each ‘species category’ were plotted together with different symbols/lines, instead of a single connected line). This suggestion was made by Reviewer 1 and was not taken up in your response, despite the very useful addition of differentiated benthic dates to Figure 2 (new Figure3). The further suggestion of Reviewer 2 to also illustrate species used in the CU record with different symbols is also a good one. The interspecies offsets remain a major unresolved issue that is worth highlighting.

2. Again on Figure 5: it is not clear to me what the lines and symbols represent. Each figure has the CU record in red, and then another line with small black symbols, where some of these small symbols also correspond to large open symbols. Please clarify in the caption what the latter two are, as it currently only refers to one dataset for each subplot as far as I can tell.

3. On the subject of the wood-based age-model: the caution and clear explanation of the fact that these dates reflect maximum ages for a given sediment depth is a welcome inclusion, however, you emphasise in your response to Reviewer 2 that an important aspect of your ‘quantitative test’ is that the wood dates are younger than both planktic and benthic dates. In this case it would be helpful to also add to Figure 2 (new Figure 3) all of the existing planktic dates, so that the reader can see how many of the wood dates can be ‘tested’ in this way. I think that it is important to acknowledge (as Zhao and Keigwin did not, but your manuscript arguably does better) that this is a situation where it is possible to know when the dates are ‘really’ wrong (e.g. by as much as the surface reservoir age), but not necessarily when they are right. I would note that a 100yr Gaussian uncertainty may not be the best way of dealing with this, given that we know the error in the wood ages is more likely to be biased in one direction (i.e. too old; ages are a maximum for a given depth). I appreciate that this is a tricky issue to address, beyond underlying the caveats, but the addition of the planktic dates to Figure 2 would help the reader see the extent to which they help act as ‘tests’ for the wood dates (and for how many).

4. On the conclusions: I concur with the reviewers that the consistency of the UC and Gulf records with others from around the word is overstated, and that perhaps some more careful wording of the conclusions is warranted, based on a consideration of a wider range of data and models For example, I think that the statement: “…a box model by (Hain et al., 2011) suggests that matching the observed ∆14C depletions in the intermediate depth, Northern Hemisphere sites requires unrealistic changes in ocean chemistry (e.g., lower surface ocean alkalinity) and ocean dynamics (i.e., mixing)” needs some further clarification (i.e. in terms of what exactly that model experiment consisted of, and was able to address strictly). Also, the statement that “evidence in support of depleted seawater 14C content during the deglaciation (although often with different timing) includes deep-sea coral ∆14C measurements in both the Southern Ocean and North Atlantic (Adkins et al., 1998; Burke and Robinson, 2012; Chen et al., 2015; Robinson et al., 2005)” is accurate but not quite apposite, since none of the coral data referenced show anything like the level of radiocarbon depletion exhibited in the Gulf and CU, and all show a step change around the Bolling-Allerod. This is a notable fact, as is the fact that the vast bulk of existing radiocarbon data from the LGM (i.e. prior to the putative ‘flushing events’) show that extreme radiocarbon depletion existed at a few sites, but was not at all widespread. 'From whence was this extremely old carbon flushed therefore?', one wonders.

I look forward to seeing your revised manuscript!

Sincerely,
Luke Skinner

Dear Patrick,
Thank you for your response and for you corrections to the manuscript. I am pleased to now be able to accept your manuscript for publication in Climate of the Past. I believe it will make a strong yet balanced contribution to what is a controversial topic where it is perhaps too easy to gloss over the tricky details. I hope that you will agree that the manuscript has benefited from the review process.

Sincerely,
luke