Dear authors:
I have now received the comments of two reviewers, which I requested, plus an additional reviewer. As you can see, all the reviewers agree that the problem of lack of replication needs to be addressed as well as the stress your instrumentation might cause to the Posidonia. At the same time, the reviewers are very favorable on the instrumentation used and its potential.
As you have indicated in your reply to the reviewers as well, there is definitely a need for a critical evaluation on potential stress responses of P. oceanica caused by your experimental system. The conclusions drawn from the study must also mention these uncertainties and potentially offer solutions to this problem.
Please provide a carefully revised version of the manuscript addressing all the comments of the reviewers in your manuscript. Also, please provide a detailed point-by-point review on how you addressed the reviewers' criticisms in the revised paper.
Best wishes, Gerhard Herndl

Dear authors:
I have now read through your revised manuscript and your response to the reviewers' comments. I find that you have satisfactorily addressed the reviewers remarks. Hence, I appreciate being able to inform you that the paper is now accepted for publication in Biogeosciences.
Thanks for choosing Biogeosciences as an outline of your interesting work.
Best wishes, Gerhard Herndl