Oxygen concentration in the water column over a Posidonia oceanica meadow in Cabrera Archipelago Marine-Terrestrial National Park between October 2019 ??? October 2021

[Description of methods used for collection/generation of data] For the study, environmental data were measured by sensors located in both the water column and the benthic compartment (at 4 m and 8 m, respectively). Temperature, salinity and dissolved oxygen (DO) from the water column were measured from October 2019 to October 2021 by a sensor attached to the mooring line. Data were recorded with a CT SBE37 (Conductivity, Temperature) sensor (SBE37SMP-ODO-RS232, Sea-Bird Scientific??) coupled with an SBE 63 (Sea-Bird Scientific??) dissolved oxygen (DO) sensor with accuracies of ?? 0.002 ??C for temperature, ?? 0.002 mS cm-1 for conductivity and ?? 2 % for DO. Measurements were taken with a resolution of 0.0001 ??C for temperature, 0.0001 mS cm???-1 for conductivity and 0.2 ??mol kg-1 for DO. Multiparametric Hydrolab HL4 probes (OTT HydroMet) were deployed during 8 different periods covering all seasons following the procedure by Hendriks et al. (2021). Accuracy for the multiparametric probe sensors is ?? 0.10 ??C for temperature and ?? 0.5 % of reading + 0.001 mS cm???1 for conductivity, with resolutions of 0.01 ??C and 0.001 mS cm-???1, respectively. The DO sensor presents an accuracy of ?? 0.1 mg L???1 for values lower than 8 mg L???1, and ?? 0.2 mg L???1 for values higher than 8 mg L???1, and a resolution of 0.01 mg L???1. Two benthic chambers were installed during May and July 2021 using a design previously described in Barr??n et al. (2006). MiniDOT sensors (PME, Inc. ??) were used for temperature and DO measurements every 15 minutes, with accuracies of ?? 0.1 ??C and ?? 5 %, respectively. DO sensor data were validated against water samples analysed with the Winkler method.. Three chamber replicates were installed during each deployment. Wind speed (m s???1) values at Cabrera NP Station were obtained from data provided by the Organismo Aut??nomo de Parques Nacionales (OAPN, Spain). For the benthic chambers, night respiration was estimated from changes in DO between one hour after sunset and one hour before sunrise. The same procedure was followed for the calculation of the net community production (NCP) during daylight hours, and the two values were summed for GPP. NCP was used along with the total meadow area coverage and residence time of water in Sta. Mar??a Bay to determine the total O2 exported by the meadow to the water column. For the metabolic rate calculation, only oxygen data from the first 24 hours were used.