I believe that the authors have made sufficient efforts to respond to the comments of the reviewers and that the paper can now be published. However, I would comment on two points raised by the reviewers.

While I agree with the authors in their comment on a question from Reviewer 1 that all is needed for Fig 4 is to show a measurable change in response, it would be good to add the changes in concentration used either in the text or in the figure caption. That that both gases give an observable change at the same time is important, but the fact that the instrument gives the same result for such different concentrations of CO2 and DMS is also of interest to potential users.

Reviewer 2’s point about the changes in fluorescence shown in Fig 9 and discussed in the text on p 18, lines 11-12 is well taken, but is not really resolvable without taking samples for chlorophyll measurement. Fluorescence quenching is certainly well-known, but there can also be changes in chlorophyll over short vertical distances. Perhaps the DMS concentrations can help here. Is there any evidence that increased DMS production occurs at higher light levels? This could tip the balance towards the authors’ contention that fluorescence quenching is occurring here.

If the authors can make these very minor changes, the paper can then be published and I do not need to see it again.

Thanks for making those changes. This looks fine to publish.