Dear Authors,

Thank you for providing detailed responses to two reviewer reports and a short comment by Fernanda Adame.

While all reviewers recognized the novelty of your manuscript, they were quite critical of your hypothesis on Fe toxicity. I agree with the reviewers and envisage that the manuscript would require a substantial revision to address reviewers’ concerns and commensurately refocus data presentation and interpretation. Therefore, I have to recommend ‘reconsider after major revisions’ and might need to ask reviewers to reassess whether the revised manuscript has provided a reasonable, data-supported interpretation of the observed biogeochemical changes and potential linkage to the mangrove dieback.

As the first reviewer suggested, please pay more attention to providing analytical details, particularly about Itrax core scanner (instrumental information, analytical accuracy, how you processed “semi-quantitative elemental profiles, etc.). In your response to the second reviewer’s comment on Fe/Mn ratio, you said that “Because we have re-shifted the focus of the manuscript away from Fe toxicity, further exploration of this data may be beyond the scope of this study.” In my view, Mn data would be still helpful for you to clear up any metal toxicity issues. I also wondered if you could compare Fe and other major metals (out of 34 elements) to single out changes in the concentration of Fe at the dieback site from drought-induced (little or small?) changes in the concentrations of other metals.

I would like to ask you to make all the changes easily identifiable in a marked-up manuscript based on your point-by-point responses to the comments offered by the reviewers and myself. Please also specify the line numbers of the marked-up manuscript in your responses to comments.

Sincerely,

Ji-Hyung Park
Associate Editor, Biogeosciences